Why can't x^2+9 be factored? And is there a way to tell if a problem can be factored or not just by looking at it?

Answer:

a)

(i) 5.8 hours

(ii)  6.5 hours

(iii) 6 hours

(iv) 6 hours

b) 180 hours

Answer:

A spurious correlation wrongly implies a cause and effect between two variables. For example, the number of astronauts dying in spacecraft is directly correlated to seatbelt use in cars: Use your seatbelt and save an astronaut life!

Interesting correlations are easy to find, but many will turn out to be spurious. Three examples are the skirt length theory, the Super Bowl indicator, and a suggested correlation between race and college completion rates.

Step-by-step explanation:

Answer:

July 4th will fall on Sunday

The date, July 4 will be Friday, the correct option is D.

Calendars represent an year of 12 months, each month has 30 or 31 days, exceptionally February has 28 days.

If today is Tuesday, May 6,

Every 7th day is going to be a Tuesday .

From May 6 to July 4, the number of days is 59

Hence we divide 59 by 7. Quotient = 8 Remainder = 3

7 x 8 = 56

56 th day is Tuesday

57 th day is Wednesday

58th day vis Thursday

59th day is Friday

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Answer:

-10 = x

Step-by-step explanation:

5=7+x/5

Subtract 7 from each side

5-7=7-7+x/5

-2 = x/5

Multiply each side by 5

-2 *5 = x/5 *5

-10 = x

Angle CBD= 81°

I hope it helps you...

Answer:

81

Step-by-step explanation:

∠CBD is the exterior angle of  the ΔABC.

Exterior angle property:

Exterior angle equals the sum of opposite interior angles.

∠CBD = ∠ABC + ∠ACB

           = 53 + 28

           = 81°

Answer:

38

Step-by-step explanation:

Angle 6 is alternate to the angle that is given as 38 degrees because line L is parallel to line M so their measure is equal.

Answer:

(4,4)

y = 4

x = 4

Step-by-step explanation:

First we need to input y = 1/2x + 2 into 4x - 2y = 8.

4x - 2 (1/2x + 2) = 8 <-- Then solve

4x - 1x + -4 = 8

3x - 4 = 8

    +4   +4

---------------------

3x    =    12

3             3

x = 4

Now we need to use x and apply it to find y.

y = 1/2x + 2

y = 1/2(4) + 2

y = 2 + 2

y = 4

Now to graph go on the x axis (horizontal axis) and go to 4, then up 4 on the y axis.

You need to graph the point (4,4).

I hope this helps!

Answer:

see graph  (4,4)

to manually graph just pick any two values for X in the first equation and calculate the corresponding Y value ... put a "dot" (a point on the graph)

do for both points , and draw al LINE between them...

repeat fore the second equation... the "solution" is where the two lines cross

Step-by-step explanation:

Answer:

x = 11√3

y = 11

Step-by-step explanation:

Let 60 be the reference angle

sin 60 = p/h

√3/2 = x/22

or, 22√3 = 2x

or, x = (22√3)/2

so, x = 11√3

now

[tex]h^2 = p^2 + b^2\\or, 22^2 = (11\sqrt{3} )^2+y^2\\or, 484 = 363 + y^2\\or, 484-363 = y^2\\or, 121 = y^2\\or, \sqrt{121} = y\\so, y = 11[/tex]

Answer:

√124

Step-by-step explanation:

Using the Pythagorean theorem, We got: x^2 + (√101)^2 = 15^2

x^2 + (√101)^2 = 15^2

x^2 = 15^2 -  (√101)^2

x^2 = 225 - 101

x^2 = 124

x = √124

The answer is √124

Answer:

-1

Step-by-step explanation:

lim x tends to 4 (x^2-9x+20)/(x-4). (x^2-9x+20)(x-4)=x-5.

So the limit is 4-5=-1

Answer:

we need to get your brain thinking in this way. that you begin to understand how to do these things.

airways to say that your brain is not working that way, is not a valid excuse. we need to change that. your brain needs to get used to this way of thinking.

so, please, please, PLEASE go through the explanations below and tell me, where exactly in these explanations you stopped understanding what I was saying. so that I can better explain to you what is happening.

1. (0, -2)

2. 4

3. a geometric sequence. the common ratio is -2.0

4. the third option

5. the fourth option

Step-by-step explanation:

1. as x increases, y decreases. until, suddenly after x=0, this tendency reverses, and with increasing x also y increases. so, this is a turning point.

2. look at the line. it only starts with x>0 (it looks like x is around 1).

"input" is all the values of x the function has a defined result for (y = result values).

so, as there is no line for negative x, we can eliminate the first 2 answers.

x=0 is no valid answer either (as mentioned above, the line only starts well after x=0).

in the answer options the only x value having an y value above or below this x value is x=4.

3. look at the difference between 2 numbers next to each other in the sequence.

2.4 to -4.8

-4.8 to 9.6

and so on.

what do we need to do to get from the left to the right ?

we need to multiply by -2.

so, the relationship between "sequence item n" (an) to "sequence item n-1" (an-1) is a ratio, a multiplication factor :

an/an-1 = -2

4. it is completely simple. a function can be many things. on an x/y coordinate grid it can have gaps, it can have sharp direction changes,...

but there us one thing a function can never have : multiple different y values for one x value.

in the first graph x=2 has two different y values (-1 and -3). so, it is not clear what the result for x=2 would be. and that means, it is not a function.

in the second graph x=4 has two different y values.

in the third graph all is OK.

in the fourth graph x=-2 has two different y values.

so, only the third option is a function.

5. this function calculates the height of the thrown rock after t seconds of flight.

therefore, only the fourth answer makes sense.

Answer:

Step-by-step explanation:

Hey GurpTheDestoyer! Find the volume of the sphere. Round to the nearest whole number. Radius= 8 what is the volume? The Volume = 2,144.660585 cm3. Hope this helped! <3

Answer:

D.-3,-1 for 4x-2y=10 y=2x-5

Answer:

B

Step-by-step explanation:

A=(3*sqrt(3)*a^2)/2

A=(3*sqrt(3)*400)/2=1038

Answer:

B.  1,038 in.2

Step-by-step explanation:

Answer:

[tex]D. \\x>\frac{3}{2}[/tex]

Step-by-step explanation:

12(1/2x - 1/3) > 8 - 2x

6x - 4 > 8 - 2x

6x + 2x - 4 > 8 - 2x + 2x

8x - 4 > 8

8x - 4 + 4 > 8 + 4

8x > 12

8x ÷ 8 > 12 ÷ 8

x  > 1.5

Answer:

BC ≈ 14.5 cm

Step-by-step explanation:

Using the sine ratio in the right triangle

sin65° = [tex]\frac{opposite}{hypotenuse}[/tex] = [tex]\frac{BC}{AB}[/tex] = [tex]\frac{BC}{16}[/tex] ( multiply both sides by 16 )

16 × sin65° = BC , then

BC ≈ 14.5 cm ( to the nearest tenth )

Answer:

y^{n+4}

Step-by-step explanation:

Answer:

Step-by-step explanation:

[tex]\frac{y^n *y^{\frac{5}{4} } }{y^{\frac{1}{4} } } =y^n*y^{\frac{5}{4} } \times y^{-\frac{1}{4} } =y^{n+\frac{5}{4} -\frac{1}{4} } \\=y^{n+\frac{5-1}{4} } \\=y^{n+\frac{4}{4} } \\=y^{n+1}[/tex]

Answer:

[tex]\mu = 47.17[/tex]

[tex]\sigma = 2.31[/tex]

Step-by-step explanation:

Solving (a): The population mean

This is calculated as:

[tex]\mu = \frac{\sum x}{n}[/tex]

So, we have:

[tex]\mu = \frac{48.2+ 47.8 +45.6 +47.2 +49.3+51.2 +44.2 +45.4 +49.2 +43.6}{10}[/tex]

[tex]\mu = \frac{471.7}{10}[/tex]

[tex]\mu = 47.17[/tex]

Solving (b): The population standard deviation

This is calculated as:

[tex]\sigma = \sqrt{\frac{\sum (x - \mu)^2}{n}}[/tex]

So, we have:

[tex]\sigma = \sqrt{\frac{(48.2-47.17)^2 + (47.8-47.17)^2 +.........+(43.6-47.17)^2}{10}}[/tex]

[tex]\sigma = \sqrt{\frac{53.521}{10}}[/tex]

[tex]\sigma = \sqrt{5.3521[/tex]

[tex]\sigma = 2.31[/tex]

Answer:

0.50 or about half a year longer.

Step-by-step explanation:

We can write an equation to model bot investments.

Oliver invested $970 in an account paying an interest rate of 7.5% compounded continuously.

Recall that continuous compound is given by the equation:

[tex]A = Pe^{rt}[/tex]

Where A is the amount afterwards, P is the principal amount, r is the rate, and t is the time in years.

Since the initial investment is $970 at a rate of 7.5%:

[tex]A = 970e^{0.075t}[/tex]

Carson invested $970 in an account paying an interest rate of 7.375% compounded annually.

Recall that compound interest is given by the equation:

[tex]\displaystyle A = P\left(1+\frac{r}{n}\right)^{nt}[/tex]

Where A is the amount afterwards, P is the principal amount, r is the rate, n is the number of times compounded per year, and t is the time in years.

Since the initial investment is $970 at a rate of 7.375% compounded annually:

[tex]\displaystyle A = 970\left(1+\frac{0.07375}{1}\right)^{(1)t}=970(1.07375)^t[/tex]

When Oliver's money doubles, he will have $1,940 afterwards. Hence:

[tex]1940= 970e^{0.075t}[/tex]

Solve for t:

[tex]\displaystyle 2 = e^{0.075t}[/tex]

Take the natural log of both sides:

[tex]\ln\left (2\right) = \ln\left(e^{0.075t}\right)[/tex]

Simplify:

[tex]\ln(2) = 0.075t\Rightarrow \displaystyle t = \frac{\ln(2)}{0.075}\text{ years}[/tex]

When Carson's money doubles, he will have $1,940 afterwards. Hence:

[tex]\displaystyle 1940=970(1.07375)^t[/tex]

Solve for t:

[tex]2=(1.07375)^t[/tex]

Take the natural log of both sides:

[tex]\ln(2)=\ln\left((1.07375)^t\right)[/tex]

Simplify:

[tex]\ln(2)=t\ln\left((1.07375)\right)[/tex]

Hence:

[tex]\displaystyle t = \frac{\ln(2)}{\ln(1.07375)}[/tex]

Then it will take Carson's money:

[tex]\displaystyle \Delta t = \frac{\ln(2)}{\ln(1.07375)}-\frac{\ln(2)}{0.075}=0.4991\approx 0.50[/tex]

About 0.50 or half a year longer to double than Oliver's money.

Answer:

6.045 * 10 ^40 ergs

1.8 * 10^-2 mm

Step-by-step explanation:

3.9 ⋅ 10^33 erg per second  * 1.55 * 10 ^7 seconds

3.9 * 1.55  * 10^(33+7)

6.045 * 10 ^40 ergs

Human hair is around .1 mm thick

.1  = 1 * 10 ^ -1

This is closer to 1.8 * 10^-2  

1.8 *10^2 = 180 mm which is too thick  This is approximately 18 cm

Answer:

6.045 * 10 ^40 ergs

1.8 * 10^-2 mm

Step-by-step explanation:

3.9 ⋅ 10^33 erg per second  * 1.55 * 10 ^7 seconds

3.9 * 1.55  * 10^(33+7)

6.045 * 10 ^40 ergs

Human hair is around .1 mm thick

.1  = 1 * 10 ^ -1

This is closer to 1.8 * 10^-2  

1.8 *10^2 = 180 mm which is too thick  This is approximately 18 cm

Step-by-step explanation:

Answer:

Step-by-step explanation:

5(a-1) -15 = 3(a+2) +4, distribute multiplication over subtraction and addition

5a -5 -15 = 3a +6 + 4, isolate the variable on one side

5a -3a = 6 +4 +5 +15, combine like terms

2a = 30, divide both sides by 2

a= 15

Answer:

45

Step-by-step explanation:

9x5

Answer:

8 units

Step-by-step explanation:

Area of a rectangle = Width multiplied by Length

Substitute in all the known numbers into this formula to get

72 = (9) × [tex](2x+4)[/tex]

Solve the equation for x, to find out the length

[tex]9(2x+4)=72[/tex]

[tex]2x+4=72/9[/tex]

[tex]2x+4=8[/tex]

[tex]2x=8-4[/tex]

[tex]2x=4[/tex]

[tex]x=4/2[/tex]

[tex]x=2[/tex]

Length of the rectangle = [tex](2x+4)[/tex]

[tex]2(2)+4[/tex]

[tex]4+4=8[/tex]

[tex]n = \frac{6}{m + 1} [/tex]

Hope it helps you...

The value of n is n= 6/( m+1).

An expression is a set of terms combined using the operations +, – , x or , /.

Given:

mn - 3 = 3 - n

mn + n = 6

n(m+ 1) =6

n= 6/( m+1)

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Let S be the sum. So you have

S = 1 + 2 + 3 + … + 2004 + 2005 + 2006

as well as

S = 2006 + 2005 + 2004 + … + 3 + 2 + 1

Then

2S = (1 + 2006) + (2 + 2005) + … + (2005 + 2) + (2006 + 1)

2S = 2007 + 2007 + … + 2007 + 2007

2S = 2006 × 2007

S = (2006 × 2007)/2

S = 2,013,021

which makes the last two digits 21.

Answer:

3 each

Step-by-step explanation:

36 / 12 = 3

.................................................

Answer:

The "zero" is where it crosses the x axis which is -2 in this graph

Step-by-step explanation:

Answer:

G = Fr² / Mm

Step-by-step explanation:

Given:

F = GMm / r²

Where,

F = Force of the two objects

M = mass of object 1

m = mass of object 2

G = constant

r = distance between the objects

Solve the formula for G.

F = GMm / r²

Cross product

F * r² = GMm

Fr² = GMm

Divide both sides by Mm

G = Fr² / Mm