Answer:
b = - 3.7
Step-by-step explanation:
here are the data values:
x y XY X²
14 46 644 196
15 49 735 225
16 37 592 256
17 42 714 289
18 37 666 324
19 31 589 361
20 25 500 400
21 23 483 441
22 20 440 484
23 15 345 529
24 12 288 576
now we are required to find the summation (total) of all values of X, Y, XY and X².
∑X = 209
∑Y = 337
∑XY = 5996
∑X² = 4081
The formular for finding b is given as:
b = n∑XY - (X)(Y) / n∑X² - (∑X)²
= 11(5996) - (209)(337) / 11(4081) - (209)²
= 65956 - 70433 / 44891 - 43681
= -4477/ 1210
= -3.7
The question asked us to find the value of b but we can go further to find the equation of the regression line:
a = ∑Y - b∑X / n
= 337 - (-3.7)(209)/ 11
=1110.3/11
= 100.94
the equation is:
Y = 100.94 - 3.7X
I hope you find my solution useful!
=
Please answer this correctly without making mistakes
Answer: 7 mi
Step-by-step explanation: since the distance from bluepoint to Manchester is 12 9/10 mi and you know that bluepoint to Silverstone is 5 9/10 subtract that and you get 7 mi as your answer
Answer:
7 miles
Step-by-step explanation:
Hey there!
Well given BM and BS, we need to subtract them.
12 9 /10 - 5 9/10
9/10 - 9/10 = 0
12 - 5 = 7
Silvergrove to Manchester is 7 miles.
Hope this helps :)
(a^8)3/2 in simplest form
Answer:
[tex]\large\boxed{\frac{3}{2}a^{8}}[/tex]
Step-by-step explanation:
([tex]a^{8}[/tex]) * [tex]\frac{3}{2}[/tex]
Remove the parenthesis by multiplying
[tex]\frac{3}{2}[/tex][tex]a^{8}[/tex]
This expression cannot be simplified further
[tex]\large\boxed{\frac{3}{2}a^{8}}[/tex]
Hope this helps :)
Consider the following ordered data. 6 9 9 10 11 11 12 13 14 (a) Find the low, Q1, median, Q3, and high. low Q1 median Q3 high (b) Find the interquartile range.
Answer:
Low Q1 Median Q3 High
6 9 11 12.5 14
The interquartile range = 3.5
Step-by-step explanation:
Given that:
Consider the following ordered data. 6 9 9 10 11 11 12 13 14
From the above dataset, the highest value = 14 and the lowest value = 6
The median is the middle number = 11
For Q1, i.e the median of the lower half
we have the ordered data = 6, 9, 9, 10
here , we have to values as the middle number , n order to determine the median, the mean will be the mean average of the two middle numbers.
i.e
median = [tex]\dfrac{9+9}{2}[/tex]
median = [tex]\dfrac{18}{2}[/tex]
median = 9
Q3, i.e median of the upper half
we have the ordered data = 11 12 13 14
The same use case is applicable here.
Median = [tex]\dfrac{12+13}{2}[/tex]
Median = [tex]\dfrac{25}{2}[/tex]
Median = 12.5
Low Q1 Median Q3 High
6 9 11 12.5 14
The interquartile range = Q3 - Q1
The interquartile range = 12.5 - 9
The interquartile range = 3.5
A particle moves according to a law of motion s = f(t), t ≥ 0, where t is measured in seconds and s in feet. (If an answer does not exist, enter DNE.) f(t) = t3 − 8t2 + 27t
The question is not clear, but it is possible to obtain distance, s, from the given function. This, I would show.
Answer:
s = 17 units
Step-by-step explanation:
Given f(t) = t³ - 8t² + 27t
Differentiating f(t), we have
f'(t) = 3t² - 16 t + 27
At t = 0
f'(t) = 27
This is the required obtainaible distance, s.
The manufacturer of a granola bar spends $1.20 to make each bar and sells them for $2. The manufacturer also has fixed costs each month of $8,000.
Answer:
C(x)=1.2x+8,000.
Step-by-step explanation:
C(x)=cost per unit⋅x+fixed costs.
The manufacturer has fixed costs of $8000 no matter how many drinks it produces. In addition to the fixed costs, the manufacturer also spends $1.20 to produce each drink. If we substitute these values into the general cost function, we find that the cost function when x drinks are manufactured is given by
In order to make the profits, the manufacturer must make the quantity of greater than 10000 bars.
What is a mathematical function, equation and expression? function : In mathematics, a function from a set X to a set Y assigns to each element of X exactly one element of Y. The set X is called the domain of the function and the set Y is called the codomain of the function.expression : A mathematical expression is made up of terms (constants and variables) separated by mathematical operators.equation : A mathematical equation is used to equate two expressions.Given is that the manufacturer of a granola bar spends $1.20 to make each bar and sells them for $2.
Suppose that you have to sell [x] number of bars to make profits. So, we can write -
{2x} - {1.20x} > {8000}
0.8x > 8000
8x > 80000
x > 10000
Therefore, in order to make the profits, the manufacturer must make the quantity of greater than 10000 bars.
To solve more questions on functions, expressions and polynomials, visit the link below -
brainly.com/question/17421223
#SPJ2
Transform the polar equation to a Cartesian (rectangular) equation: r= 4sinθ
options include:
x^2+y^2 = 4y
x^2+y^2 = -4
x^2+y^2 = 4
x^2+y^2 = -4y
Answer:
x^2 +y^2 = 4y
Step-by-step explanation:
Using the usual translation relations, we have ...
r^2 = x^2+y^2
x = r·cos(θ)
y = r·sin(θ)
Substituting for sin(θ) the equation becomes ...
r = 4sin(θ)
r = 4(y/r)
r^2 = 4y
Then, substituting for r^2 we get ...
x^2 +y^2 = 4y . . . . . matches the first choice
. A discount brokerage selected a random sample of 64 customers and reviewed the value of their accounts. The mean was $32,000 with a population standard deviation of $8,200. What is a 90% confidence interval for the mean account value of the population of customers
Answer:
The 90% confidence interval is [tex]\$ \ 30313.9< \mu < \$ \ 33686.13[/tex]
Step-by-step explanation:
From the question we are told that
The sample size is n = 64
The sample mean is [tex]\= x = \$ 32, 000[/tex]
The standard deviation is [tex]\sigma= \$ 8, 200[/tex]
Given that the confidence interval is 90% then the level of significance is mathematically evaluated as
[tex]\alpha = 100 - 90[/tex]
[tex]\alpha = 10 \%[/tex]
[tex]\alpha = 0.10[/tex]
Next we obtain the critical value of [tex]\frac{ \alpha }{2}[/tex] from the normal distribution table , the value is
[tex]Z_{\frac{\alpha }{2} } = 1.645[/tex]
Generally the margin of error is mathematically represented as
[tex]E = Z_{\frac{\alpha }{2} } * \frac{ \sigma }{ \sqrt{n} }[/tex]
=> [tex]E = 1.645 * \frac{ 8200 }{ \sqrt{64} }[/tex]
=> [tex]E = 1686.13[/tex]
The 90% confidence interval is mathematically represented as
[tex]\= x - E < \mu < \= x + E[/tex]
=> [tex]32000 - 1689.13 < \mu < 32000 + 1689.13[/tex]
=> [tex]\$ \ 30313.9< \mu < \$ \ 33686.13[/tex]
3.24 (4 being repeated) to a fraction
Answer:
146/45
Step-by-step explanation:
Let x represent the value of the number of interest. Then we can do the following math to find its representation as a fraction.
[tex]x=3.2\overline{4}\\10x=32.4\overline{4}\\10x-x=9x=32.4\overline{4}-3.2\overline{4}=29.2\\\\x=\dfrac{29.2}{9}=\boxed{\dfrac{146}{45}}[/tex]
__
Comment on procedure
The power of 10 that we multiply by (10x) is the number of repeated digits. Here, there is a 1-digit repeat, so we multiply by 10^1. If there were a 2-digit repeat, we would compute 10^2x -x = 99x to rationalize the number.
Jilk Inc.'s contribution margin ratio is 62% and its fixed monthly expenses are $45,000. Assuming that the fixed monthly expenses do not change, what is the best estimate of the company's net operating income in a month when sales are $132,000?
Answer: $ 36,840.
Step-by-step explanation:
contribution margin=62% =0.62
fixed monthly expenses = $45,000
Sales = $132,000
We assume that the fixed monthly expenses do not change.
Then, company's net operating income = (contribution margin×Sales )-fixed monthly expenses
=$( (0.62×132000)-45000 )
= $ (81840-45000)
= $ 36,840
Hence, the best estimate of the company's net operating income in a month when sales are $132,000 is $ 36,840.
Find the sum of (5x3 + 3x2 - 5x + 4) and (8x3 -5x2 + 8x + 9)
Answer:
(5x³+3x²-5x+4) + (8x³-5x²+8x+9)
= 5x³+3x²-5x+4 +8x³-5x²+8x+9
= 5x³+8x³+3x²-5x²-5x+8x+4+9
= 13x³-2x²+3x+13
Hope this helps
if u have question let me know in comments ^_^
A machine fills boxes weighing Y lb with X lb of salt, where X and Y are normal with mean 100 lb and 5 lb and standard deviation 1 lb and 0.5 lb, respectively. What percent of filled boxes weighing between 104 lb and 106 lb are to be expected?
a. 67%
b. None
c. 37%
d. 57%
Answer:
Option b. None is the correct option.
The Answer is 63%
Step-by-step explanation:
To solve for this question, we would be using the z score formula
The formula for calculating a z-score is given as:
z = (x-μ)/σ,
where
x is the raw score
μ is the population mean
σ is the population standard deviation.
We have boxes X and Y. So we will be combining both boxes
Mean of X = 100 lb
Mean of Y = 5 lb
Total mean = 100 + 5 = 105lb
Standard deviation for X = 1 lb
Standard deviation for Y = 0.5 lb
Remember Variance = Standard deviation ²
Variance for X = 1lb² = 1
Variance for Y = 0.5² = 0.25
Total variance = 1 + 0.25 = 1.25
Total standard deviation = √Total variance
= √1.25
Solving our question, we were asked to find the percent of filled boxes weighing between 104 lb and 106 lb are to be expected. Hence,
For 104lb
z = (x-μ)/σ,
z = 104 - 105 / √25
z = -0.89443
Using z score table ,
P( x = z)
P ( x = 104) = P( z = -0.89443) = 0.18555
For 1061b
z = (x-μ)/σ,
z = 106 - 105 / √25
z = 0.89443
Using z score table ,
P( x = z)
P ( x = 106) = P( z = 0.89443) = 0.81445
P(104 ≤ Z ≤ 106) = 0.81445 - 0.18555
= 0.6289
Converting to percentage, we have :
0.6289 × 100 = 62.89%
Approximately = 63 %
Therefore, the percent of filled boxes weighing between 104 lb and 106 lb that are to be expected is 63%
Since there is no 63% in the option, the correct answer is Option b. None.
The percent of filled boxes weighing between 104 lb and 106 lb is to be expected will be 63%.
What is a normal distribution?It is also called the Gaussian Distribution. It is the most important continuous probability distribution. The curve looks like a bell, so it is also called a bell curve.
The z-score is a numerical measurement used in statistics of the value's relationship to the mean of a group of values, measured in terms of standards from the mean.
A machine fills boxes weighing Y lb with X lb of salt, where X and Y are normal with a mean of 100 lb and 5 lb and standard deviation of 1 lb and 0.5 lb, respectively.
The percent of filled boxes weighing between 104 lb and 106 lb is to be expected will be
Then the Variance will be
[tex]Var = \sigma ^2[/tex]
Then for X, we have
[tex]Var (X) = 1^2 = 1[/tex]
Then for Y, we have
[tex]Var (Y) = 0.5^2 = 0.25[/tex]
Then the total variance will be
[tex]Total \ Var (X+Y) = 1 + 0.25 = 1.25[/tex]
The total standard deviation will be
[tex]\sigma _T = \sqrt{Var(X+Y)}\\\\\sigma _T = \sqrt{1.25}[/tex]
For 104 lb, then
[tex]z = \dfrac{104-105}{\sqrt{25}} = -0.89443\\\\P(x = 104) = 0.18555[/tex]
For 106 lb, then
[tex]z = \dfrac{106-105}{\sqrt{25}} = 0.89443\\\\P(x = 106) = 0.81445[/tex]
Then
[tex]P(104 \leq Z \leq 106) = 0.81445 - 0.18555 = 0.6289 \ or \ 62.89\%[/tex]
Approximately, 63%.
More about the normal distribution link is given below.
https://brainly.com/question/12421652
What is 5 feet and 11 inches in inches
Answer:
60
Step-by-step explanation:
5 is 60 inch
How should a musician effectively convey emotions or ideas in a performance?
Answer:
Within the factors hindering expression in music, tempo is the most important number of factors such as your mood.
Step-by-step explanation:
If one wants to convey a message, they should try these:
a) Use real life
b) introduce symbolism
c) convey sensory disruption, e.t.c.
Hope these helps.
The value (in dollars) of an airplane depends on the flight hours as given by the formula V= 1,800,000 - 250x . After one year, the value of the plane is between $1,200,000 and $1,300,000. Which range for the flight hours does this correspond to?
a. 1800 <= x <= 2100
b. 2200<= x <= 2500
c. 1500<= x <= 1800
d. 2000<= x <= 2400
Answer:
D
Step-by-step explanation:
To determine the range we must solve this inequality;
● 1200000<1800000-250x<1300000
Substract 1800000 from both sides.
● 1200000-1800000<1800000-250x<1300000-1800000
● -600000< -250x < -500000
Divide both sides by 250
● -600000/250 < -250x/250 < -500000/250
● -2400 < -x < -2000
Multiply both sides by -1 and switch the signs
● 2000 < x < 2400
The correct option is D. 2000<= x <= 2400
Given, the value of an airplane depends on the flight hours,
[tex]V= 1800000-250x[/tex], here x is the flight hours.
We have to calculate the range of x After one year.
Since, [tex]V= 1800000-250x[/tex]
[tex]250x=1800000-V\\\\x=\dfrac{1800000-V}{250}[/tex]
Since the value of the plane is between $1,200,000 and $1,300,000. So,
[tex]x=\dfrac{1800000-1200000}{250}[/tex]
[tex]x=\dfrac{600000}{250}[/tex]
[tex]x=2400\\[/tex]
When V is 1300000 then x will be,
[tex]x=\dfrac{1800000-1300000}{250} \\[/tex]
[tex]x=\dfrac{500000}{250}[/tex]
[tex]x=2000[/tex]
Hence the range of x will be from 2000 to 2400.
The correct option is D. 2000<= x <= 2400.
For more details on range follow the link:
https://brainly.com/question/10185991
The formula for the area of a square is s2, where s is the side length of the square. What is the area of a square with a side length of 6 centimeters? Do not include units in your answer.
Answer:
36
Step-by-step explanation:
formula of area for square:
A=s^2
s=6
A=6^2
A=36
Answer:
36
Step-by-step explanation:
I got it right
Solve for 2 in the diagram below.
120°
32°
T=
Step-by-step explanation:
Hello, there!!!
It's so simple here,
Here,
we have is 1 angle is 120°and other is 3x°.
now,
3x°=120° {because when two st.line intersects eachother then the opposite angle formed are equal}
so, 3x°=120
or, x=120°/3
=40°
Therefore, the value of x is 40°.
Hope it helps....
14. Twice the sum of a number and eight
Answer: 2(x + 8) is the expression.
Use distributive property to simplify,
2x+16
I didn't know which answer you wanted so....
Answer:
2(x + 8)
Step-by-step explanation:
Hello!
Twice the sum means we multiply by 2
2
the sum of a number and eight is x + 8
2 * x + 8
Since we have to twice the sum we put x + 8 in parenthesis to show to do that first
2(x + 8)
Hope this Helps!
Please answer this correctly without making mistakes
Answer:
so to get a third you divide it by 3
first convert it to fraction
so it is 26/3
so do 26/3 divided by 3
so we do keep switch flip
26/3*1/3
so answer is 26/9 or 2 8/9
Step-by-step explanation:
Answer:
[tex]\large \boxed{\mathrm{2 \ 8/9 \ tablespoons \ of \ red \ chilies }}[/tex]
Step-by-step explanation:
8 2/3 tablespoons of red chilies is required for a recipe.
One-third of the original recipe would mean that the quantity of red chilies will be also one-third.
8 2/3 × 1/3
Convert to an improper fraction.
26/3 × 1/3
Multiply the fractions.
26/(3 × 3) = 26/9
Convert to a mixed fraction.
26/9 = 2 8/9
Find the number of pieces of floor tiles each measuring 26cm long and 10cm wide needed to lay a floor measuring 260m long and 15m wide
Answer:
150,000
Step-by-step explanation:
1 m = 100 cm
260 m = 260 * 100 cm = 26000 cm
15 m = 15 * 100 cm = 1500 cm
area of floor = LW = 26000 cm * 1500 cm = 39,000,000 cm^2
area of 1 tile = 26 cm + 10 cm = 260 cm^2
number of tiles needed = 39,000,000/260 = 150,000
Answer: 150,000 tiles
How do you find x when knowing the probability?
Answer:
x
Step-by-step explanation:
probability is the branch of mathematics concerning numeral descriptions of how likely an event is to occur or how likely it is that a proposition is true
write a thirdthird-degree polynomial expression that has only two terms with a leading term that has a coefficient of five and a constant of negative two
Answer:
5x^3-2
[tex]ax^{3} +bx^{2} +cx+d\\5x^{3}-given\\ d=-2-given\\5x^{3} -2[/tex]
Explanation:
The two terms are [tex]5x^3[/tex] and [tex]2[/tex]. Terms are separated by either a plus or minus.
We can write it as [tex]5x^3+(-2)[/tex] which is an equivalent form. Here the two terms are [tex]5x^3[/tex] and [tex]-2[/tex]. This is because adding a negative is the same as subtracting.
The coefficient is the number to the left of the variable.
The degree is the largest exponent, which helps form the leading term.
The third degree polynomial written above is considered a cubic binomial. "Cubic" refers to the third degree, while "binomial" means there are 2 terms.
We can write something like [tex]5x^3[/tex] as 5x^3 when it comes to computer settings.
On a coordinate plane, 2 lines are shown. Line A B has points (negative 4, negative 2) and (4, 4). Line C D has points (0, negative 3) and (4, 0). Which statement best explains the relationship between lines AB and CD? They are parallel because their slopes are equal. They are parallel because their slopes are negative reciprocals. They are not parallel because their slopes are not equal. They are not parallel because their slopes are negative reciprocals.
Answer:
A. they are parallel because their slopes are equal.
Step-by-step explanation:
edge 2020
Answer:
its A in egde
Step-by-step explanation:
A random variable is not normally distributed, but it is mound shaped. It has a mean of 14 and a standard deviation of 3. If you take a sample of size 10, can you say what the shape of the sampling distribution for the sample mean is
Answer:
Step-by-step explanation:
from the question,
the mean 14
the standard deviation is 3
and sample size is 10.
since the n which is the sample size is 10, then the distribution is mound shaped.
why?
this is due to the fact that the random variable from which we took the sample is mound shaped.
The sampling distribution of the mean is normally distributed although the question says the random variable is not normally distributed. so the shape is bell shaped and normally distributed.
the standard deviation of the mean is
3/√10
= 0.948
A study collects samples of water from the tap in Vacaville and from bottled water available from the Nugget stores and samples their pH levels. The results are in the table below. I find a bottle marked #13 but cannot read the label for the type of water. He measures the pH and gets 6.32. What type of water do you think it is?
Answer:
see below
Step-by-step explanation:
the observed ph is 6.32
the mean pH of Tap water is shown below
sum of observations
Mean (Tap) = -----------------------------------
number of observations
(7.24 +7.05 +7.07 +6.6 +7.28 +7.29 +7.05 +6.7 +7.16 +7.07 +7.12 +6.56
= ---------------------------------------------------------------------------------------------------------
12
= 7.016
then mean pH of bottle water is shown below
sum of observations
Mean (Bottles) = -----------------------------------
number of observations
(5.35 + 5.29 + 5.46 + 5.4 + 5.95 + 6.22 + 5.43 +5.48 +6.06 +5.33 +5.46 +5.41)
= --------------------------------------------------------------------------------------------------------------
12
= 5.57
theoretically.. the higher the pH values should be between 0 to 14.
based from the above results, the mean tap water has an average of 7.016 and by looking at the pH chart... its a neutral or pure water.
while the average pH Bottles has 5.57, this means its more acidic water, or by looking at the pH chart its an acid rain water.
a 6.32pH is below pure water, based on the chart looks like a urine/saliva.
Given: f(x) = x + 2 and g(x) = x2 +3, find the following:
28) f(-3)
29) f(g(2))
30) g(f(x))
31) f-1(x)
Answer:
28) -1
29) 9
30) x^2+4x+7
31) x-2
Step-by-step explanation:
Given:
f(x) = x + 2
g(x) = x^2 +3
Find:
28) f(-3)
29) f(g(2))
30) g(f(x))
31) f-1(x)
Solution:
Put the function argument values into the expression and do the arithmetic.
28) f(-3) = (-3) +2 = -1
__
29) f(g(2)) = f((2)^2 +3) = f(7) = (7) +2 = 9
__
30) g(f(x)) = g(x+2) = (x+2)^2 +3 = x^2 +4x +7
__
31) The meaning of y = f^-1(x) is x = f(y).
x = f(y) = y+2
y = x -2
f^-1(x) = x -2
What is the slope of a line perpendicular to y=-7/4x
O A.
IN
O B.
7
O c.
4
-
O D.
7
4
Answer:
y=4/7x
Step-by-step explanation:
perpendicular lines have opposite slopes. that means reciprocal and opposite sign.
Let A and B be any two sets. Show that:
Show that (
AUB)', (BUA)' = 0
Step-by-step explanation:
(AUB)' means they are all outside the set A and B so thats 0. Hope it helps
A survey showed that among 785 randomly selected subjects who completed four years of college, 144 of them are smokers and 84 do not smoke (based on data from the American Medical Association). Suppose you want to test at the 0.01 significance level the claim that the rate of smoking among those with four years of college is less than the 27% rate for the general population.
A. State the null and alternative hypotheses.
B. Find the sample statistic and the p-value.
C. What is your conclusion?
Answer:
We conclude that the rate of smoking among those with four years of college is less than the 27% rate for the general population.
Step-by-step explanation:
We are given that a survey showed that among 785 randomly selected subjects who completed four years of college, 144 of them are smokers.
Let p = population proportion of smokers among those with four years of college
So, Null Hypothesis, [tex]H_0[/tex] : p [tex]\geq[/tex] 27% {means that the rate of smoking among those with four years of college is more than or equal to the 27% rate for the general population}
Alternate Hypothesis, [tex]H_A[/tex] : p < 27% {means that the rate of smoking among those with four years of college is less than the 27% rate for the general population}
The test statistics that will be used here is One-sample z-test for proportions;
T.S. = [tex]\frac{\hat p-p}{\sqrt{\frac{p(1-p)}{n} } }[/tex] ~ N(0,1)
where, [tex]\hat p[/tex] = sample proportion of smokers = [tex]\frac{144}{785}[/tex] = 0.18
n = sample of subjects = 785
So, the test statistics = [tex]\frac{0.18-0.27}{\sqrt{\frac{0.27(1-0.27)}{785} } }[/tex]
= -5.68
The value of z-test statistics is -5.68.
Also, the P-value of the test statistics is given by;P-value = P(Z < -5.68) = Less than 0.0001
Now, at a 0.01 level of significance, the z table gives a critical value of -2.3262 for the left-tailed test.
Since the value of our test statistics is less than the critical value of z, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region.
Therefore, we conclude that the rate of smoking among those with four years of college is less than the 27% rate for the general population.
What is the volume of a cube with a side length of
of a unit?
If f(x)=ax+b/x and f(1)=1 and f(2)=5, what is the value of A and B?
Answer:
[tex]\huge\boxed{a=9 ; b = -8}[/tex]
Step-by-step explanation:
[tex]f(x) = \frac{ax+b}{x}[/tex]
Putting x = 1
=> [tex]f(1) = \frac{a(1)+b}{1}[/tex]
Given that f(1) = 1
=> [tex]1 = a + b[/tex]
=> [tex]a+b = 1[/tex] -------------------(1)
Now,
Putting x = 2
=> [tex]f(2) = \frac{a(2)+b}{2}[/tex]
Given that f(2) = 5
=> [tex]5 = \frac{2a+b}{2}[/tex]
=> [tex]2a+b = 5*2[/tex]
=> [tex]2a+b = 10[/tex] ----------------(2)
Subtracting (2) from (1)
[tex]a+b-(2a+b) = 1-10\\a+b-2a-b = -9\\a-2a = -9\\-a = -9\\a = 9[/tex]
For b , Put a = 9 in equation (1)
[tex]9+b = 1\\Subtracting \ both \ sides \ by \ 9\\b = 1-9\\b = -8[/tex]
