it takes Bert 30 minutes longer to mow a rectangular lawn that measures 30 feet by 25 feet than it takes him to mow a rectangular lawn that measures 20 feet by 15 feet. if he mows the two lawns at the same rate per square foot, how long does it take him to mow both lawns ?

A)50min
B)60min
C)70min
D)80min

Answer:

y = 3x^2-6x+3    one real solution  

y = -x^2 - 4x + 7     two real solution

y = -2x^2+9x-11       two complex solutions

Step-by-step explanation:

b^2-4ac = 0   1 repeated real solution

b^2-4ac > 0   2 distinct real solutions

b^2-4ac < 0   2 complex solutions

The quadratic functions have the following solutions:

y = 3x²-6x+3 has two real solutions.

y = -x² - 4x + 7 has one real solution.

y = -2x²+9x-11 has one complex solution.

The given quadratic functions are y = 3x²-6x+3, y = -x² - 4x + 7 and y = -2x²+9x-11.

The discriminant of a quadratic equation ax² + bx + c = 0 is in terms of its coefficients a, b, and c. i.e., Δ OR D = b² − 4ac.

Now, with the function y = 3x²-6x+3, we get

b² − 4ac=(-6)²-4×3×3=36-36=0

Since b=0 it has two real solutions.

Now, with the function y = -x² - 4x + 7, we get

b² − 4ac= (-4)²-4×(-1)×7=16+28=44

Since b>0 it has one real solutions.

Now, with the function y = -2x²+9x-11, we get

b² − 4ac= (9)²-4×(-2)×(-11)=81-88=-7

Since b<0 it has one complex solution.

Therefore, the quadratic functions have the following solutions:

y = 3x²-6x+3 has two real solutions.

y = -x² - 4x + 7 has one real solution.

y = -2x²+9x-11 has one complex solution.

To learn more about the quadratic function solutions visit:

https://brainly.com/question/1687230.

#SPJ2

Any linear equation can be written as

y = mx+b

where m is the slope and b is the y intercept

m = 1/2 in this case. It represents the idea that the snow fell at a rate of 1/2 inch per hour. In other words, the snow level went up 1/2 an inch each time an hour passed by.

b = 8 is the y intercept. It's the starting amount of snow. We start off with 8 inches of snow already.

The info "snow fell for 9 hours" doesn't appear to be relevant here.

Answer:

4th option

Step-by-step explanation:

6/sin(65) = 5/sin(x)

or, 6×sin(x) = 5×sin(65)

or, sin(x) = 5×sin(65)/6

or, x = arcsin(5×sin(65)/6)

Answer:

-2

Step-by-step explanation:

GIVEN :-

x = 5 and y = 12

TO FIND :-

2x - y

SOLUTION :-

placing the values of x and y

(2 × 5) - 12

10 - 12

-2

Answer:

4 cm by 5 cm (4 x 5)

Step-by-step explanation:

The area of a rectangle with length [tex]l[/tex] and width [tex]w[/tex] is given by [tex]A=lw[/tex]. Since the length of the rectangle is 7 less than 3 times its width, we can write the length as [tex]3w-7[/tex]. Therefore, substitute [tex]l=3w-7[/tex] into [tex]A=lw[/tex]:

[tex]A=lw,\\20=(3w-7)w[/tex]

Distribute:

[tex]20=3w^2-7w[/tex]

Subtract 20 from both sides:

[tex]3w^2-7w-20=0[/tex]

Factor:

[tex](w-4)(3w+5)=0,\\\begin{cases}w-4=0, w=\boxed{4},\\3w+5=0, 3w=-5, w=\boxed{-\frac{5}{3}}\end{cases}[/tex]

Since [tex]w=-\frac{5}{3}[/tex] is extraneous (our dimensions cannot be negative), our answer is [tex]w=4[/tex]. Thus, the length must be [tex]20=4l, l=\frac{20}{4}=\boxed{5}[/tex] and the dimension of the rectangle are 4 cm by 5 cm (4 x 5).

Answer:

165 hits

Step-by-step explanation:

27.5% of 600 is 600 x 27.5 / 100 = 165

Answer:

Option A, 80π

Step-by-step explanation:

4²×5π

= 80π

Answer: Either C or D (explanation below)

=========================================================

Explanation:

Let's go through the answer choices to see which are true or which are false. The goal is to find which is false.

Unfortunately, we found C and D to be false. So it's not clear if there's a typo or if your teacher meant to say something else.

Answer:

P(Ac and Bc) = 7/36 = 0.1944 = 19.44%

Step-by-step explanation:

A probability is the number of desired outcomes divided by the number of total outcomes.

Possible outcomes:

For the pair of dice:

(1,1), (1,2), (1,3), (1,4), (1,5), (1,6)

(2,1), (2,2), (2,3), (2,4), (2,5), (2,6)

(3,1), (3,2), (3,3), (3,4), (3,5), (3,6)

(4,1), (4,2), (4,3), (4,4), (4,5), (4,6)

(5,1), (5,2), (5,3), (5,4), (5,5), (5,6)

(6,1), (6,2), (6,3), (6,4), (6,5), (6,6)

So 36 total outcomes.

Find P(Ac and Bc).

Complement of A(The result of the sum is different of 8) and complement of B(multiply to odd number). So the desired events are:

(1,1), (1,3), (1,5)

(3,1), (3,3)

(5,1), (5,5)

7 desired outcomes. So

P(Ac and Bc) = 7/36 = 0.1944 = 19.44%

Answer:

4x + 3 = 59

x = 14

Step-by-step explanation:

The vertical angles theorem states that when two lines intersect, the angles opposite each other are congruent. One can apply this here by stating the following:

4x + 3 = 59

Solve for (x), use inverse oeprations:

4x + 3= 59

4x = 56

x = 14

Answer:

Relationship : Vertical angle

Step-by-step explanation:

(4x + 3) = 59

4x = 59 - 3

4x = 56

x = 56/4

x = 14

Answer:

869/50

Step-by-step explanation:

17.38

= 1738/100

= 869/50

Answer:

The critical value for the 90% confidence interval is [tex]Z_c = 1.645[/tex].

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]1-\alpha[/tex], we have the following confidence interval of proportions.

[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

In which

z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].

90% confidence level

So [tex]\alpha = 0.1[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.1}{2} = 0.95[/tex], so [tex]Z = 1.645[/tex].

The critical value for the 90% confidence interval is [tex]Z_c = 1.645[/tex].

Answer:

20 + 10 = blank × (4 + 2)

30 = blank × 6

blank = 30 ÷ 6 = 5

Answer:

The given differential equation is

x ² (y' - x ²) + 3xy = cos(x)

Expanding and rearranging terms, we get

x ² y' + 3xy = cos(x) + x ⁴

Multiply both sides by x, which is motivated by the fact that (x ³)' = 3x ².

x ³ y' + 3x ²y = x cos(x) + x ⁵

The left side is the derivative of a product:

(x ³y)' = x cos(x) + x ⁵

Integrate both sides with respect to x :

∫ (x ³y)' dx = ∫ (x cos(x) + x ⁵) dx

x ³y = cos(x) + x sin(x) + 1/6 x ⁶ + C

Solve for y. Since x > 0, we can safely divide both sides by x ³.

y = cos(x)/x ³ + sin(x)/x ² + 1/6 x ³ + C/x³

Answer:

[tex]P(O\ or\ A) = 0.85[/tex]

Step-by-step explanation:

Given

See attachment

Required

[tex]P(O\ or\ A)[/tex]

From the question, we understand that she can only get blood from O or A groups. So, the probability is represented as:

[tex]P(O\ or\ A)[/tex]

This is calculated as:

[tex]P(O\ or\ A) = P(O) + P(A)[/tex]

Using the American row i.e. the blood must come from an American.

We have:

[tex]P(O) = 0.45[/tex]

[tex]P(A) = 0.40[/tex]

So, we have:

[tex]P(O\ or\ A) = 0.45 + 0.40[/tex]

[tex]P(O\ or\ A) = 0.85[/tex]

Answer:

68% of the time, John's grades will be between 55 and 85, while for Jane, 68% of the time, her grades will be between 65 and 75. They have the same mean grade, however, due to the lower standard deviation, Jane is more consistent, while John has the higher upside.

Step-by-step explanation:

The Empirical Rule states that, for a normally distributed random variable:

Approximately 68% of the measures are within 1 standard deviation of the mean.

Approximately 95% of the measures are within 2 standard deviations of the mean.

Approximately 99.7% of the measures are within 3 standard deviations of the mean.

John:

Mean of 70, standard deviation of 15.

70 - 15 = 55

70 + 15 = 85

68% of the time, John's grades will be between 55 and 85.

Jane:

Mean of 70, standard deviation of 5.

70 - 5 = 65

70 + 6 = 75.

68% of the time, Jane's grades will be between 65 and 75.

Describe the two students in terms of consistency of their grades and give reason.

68% of the time, John's grades will be between 55 and 85, while for Jane, 68% of the time, her grades will be between 65 and 75. They have the same mean grade, however, due to the lower standard deviation, Jane is more consistent, while John has the higher upside.

Answer:

m║n

Step-by-step explanation:

If two lines 'line m' and 'line n' are perpendicular to the 'line t', both the lines 'm' and 'n' will be parallel to each other.

If m ⊥ l and n ⊥ l, then m║n.

Answer:

60 and 40

Step-by-step explanation:

As they are complementary, their sum will be 90. 5x+4x-18=90, 9x=108, x=12

Answer:

C 9i

D -9i

Step-by-step explanation:

sqrt(-81)

sqrt(81) sqrt(-1)

we know that sqrt(-1) = i

±9i

Answer:

Y =4X  -3

Step-by-step explanation:

x1 y1  x2 y2

1 1  -2 -11

(Y2-Y1) (-11)-(1)=   -12  ΔY -12

(X2-X1) (-2)-(1)=    -3  ΔX -3

slope= 4          

B= -3          

Y =4X  -3    

Answer:

y=4x-3

Step-by-step explanation:

Hi there!

We are given the points (1,1) and (-2, -11) and we want to write the equation of the line in slop-intercept form

Slope-intercept form is given as y=mx+b, where m is the slope and b is the y intercept

So let's find the slope of the line

The formula for the slope calculated from two points is [tex]\frac{y_2-y_1}{x_2-x_1}[/tex], where [tex](x_1, y_1)[/tex] and [tex](x_2, y_2)[/tex] are points

We have everything we need to calculate the slope, let's just label the points to avoid confusion

[tex]x_1=1\\y_1=1\\x_2=-2\\y_2=-11[/tex]

Now substitute those values into the formula

m=[tex]\frac{y_2-y_1}{x_2-x_1}[/tex]

m=[tex]\frac{-11-1}{-2-1}[/tex]

Subtract

m=[tex]\frac{-12}{-3}[/tex]

Divide

m=4

So the slope of the line is 4

Here is the equation of the line so far:

y=4x+b

We need to find b

As the equation passes through both (1,1) and (-2, -11), we can plug either one of them into the equation to solve for b

Taking (1,1) will give us this:

1=4(1)+b

Multiply

1=4+b

Subtract 4 from both sides

-3=b

Substitute -3 as b into the equation

y=4x-3

Hope this helps!

Answer:

Number of planes on the runway or waiting to take off is approximately 2

Step-by-step explanation:

Given the data in the question;

On average there are 21 planes taking off per hour

rate of flow = frequency of take off = 21 planes / hr

= 21 planes per 60 minutes

= 0.35 planes/min

Now, we get the throughput time

throughput time = total time for take off =  waiting time on runway + run time on runway

= (4 minutes and 21 seconds) + 27 seconds

= 4.35 minutes + 0.45 minutes

= 4.8 minutes

Now, using Little's law;

Number of planes on the runway or waiting to take off will be;

N = Rate of flow × throughput time

we substitute

N = ( 0.35 planes/min ) × 4.8 min

N = 1.68 planes ≈ 2 planes

Therefore, Number of planes on the runway or waiting to take off is approximately 2

Answer:

1 = - 4 - 14 √3

2 = 9 - 11 √3

Step-by-step explanation:

Question 1

(-4√3 + 2)(√3 + 4)

Apply FOIL method

= (-4√3) √3 + (-4√3) . 4 + 2 √3 + 2 . 4

Apply minus-plus rules: + (-a) = -a

= -4 √3 √3 - 4 . 4 √3 + 2 √3 + 2 . 4

Simplify

= - 4 - 14 √3

Question 2

(-3 + √3)(1 + 4 √3)

Apply FOIL method

= (-3) . 1 + (-3) . 4 √3 + √3 . 1 + √3 . 4 √3

Apply minus-plus rules: + (-a) = -a

= -3 . 1 - 3 . 4 √3 + 1 . √3 + 4 √3 √3

Simplify

= 9 - 11 √3

Answer:

qualitative

Step-by-step explanation:

bcos the question is in quality format

Answer:

we are armysss!!!!\

hiiiiiiiiii

yoooooooo

heyyyyyy

brainlist meeee!

9514 1404 393

Answer:

Step-by-step explanation:

The place value of a digit to the right of the decimal point is 10 to the negative power of the digit count. The 1st digit right of the decimal point has a place value of 10^-1.

Here, the most significant digit of 0.000000016 is in the 8th place to the right of the decimal point, so its place value is 10^-8.

  0.000000016 = 1.6×10^-8

Another way to write the same number is 1.6E-8. (The "E" is a stand-in for ×10^.)

_____

Your (graphing or scientific) calculator or a spreadsheet can display this in scientific notation for you.

__

That many nanoseconds, as this problem states, would be 1.6×10^-17 seconds. "Nano" is an SI prefix meaning 10^-9.

Answer: $1,084 per person

Step-by-step explanation:

divide 32520 by 30