Find f(-5) if f(n) = n^3 + 3n^2

Please help and show steps so i could figure out how to do it , will give branliest!

erastova [34]

Answer:

8

Step-by-step explanation:

1. 3b - 2 (1 - b) / a - 2

2. 3(2) - 2 (1 - 2) / 3 - 2

3. 6 - 2 (-1) / 1

4. 6 + 2 / 1

5. 8 / 1

6. 8

3 0

2 years ago

Nine scores have an average of 8. Scores x and x+1 are added, and these increase the average to 9. Find x

Degger [83]

Answer:

x must be 13

Step-by-step explanation:

Represent the nine scores by a, b, c, d, e, f, g, h, i.

Write the following equation to indicate that the average of these nine scores is 8:

a+b+c+d+e+f+g+h+i

----------------------------- = 8, or <em>a+b+c+d+e+f+g+h+i = 72</em> if we multiply both

9 sides of this equation by 9.

Next, we add scores x and x+ 1 to

a+b+c+d+e+f+g+h+i + x + x + 1

and divide the result by 11, as there are now 11 scores instead of just 9:

a+b+c+d+e+f+g+h+i + x + x + 1

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

11

Earlier, we saw that a+b+c+d+e+f+g+h+i = 72. We can now replace

a+b+c+d+e+f+g+h+i in the above fraction by 72:

72 + 2x + 1

------------------- = 9 (as the new average is 9)

11

Multiplying both sides of this equation by 11 results in:

73 + 2x = 99, or 2x = 26.

Then x must be 13, and x + 1 must be 14.

3 0

3 years ago

a map of South Carolina is being made to a scale of 1/2 inches equals 50 miles. Greenville is 230 miles from Myrtle beach. how f

Olin [163]

All you have to do here is multiply 230 by .5 and you get 115.

They are 115 inches apart on the map.

Hope this helped! :)

7 0

3 years ago

Read 2 more answers

An oil refinery is located on the north bank of a straight river that is 2 km wide. A pipeline is to be constructed from the ref

hichkok12 [17]

Answer:

P is exactly 3km east from the oil refinery.

Step-by-step explanation:

Let's d be the distance in km from the oil refinery to point P. So the horizontal distance from P to the storage is 3 - d and the vertical distance is 2. Hence the diagonal distance is:

$\sqrt{(3 - d)^2 + 2^2} = \sqrt{(3 - d)^2 + 4}$

So the cost of laying pipe under water with this distance is

$800000\sqrt{(3 - d)^2 + 4}$

And the cost of laying pipe over land from the refinery to point P is 400000d. Hence the total cost:

$800000\sqrt{(3 - d)^2 + 4} + 400000d$

We can find the minimum value of this by taking the 1st derivative and set it to 0

$800000\frac{2*0.5*(3-d)(-1)}{\sqrt{(3 - d)^2 + 4}} + 400000 = 0$

We can move the first term over to the right hand side and divide both sides by 400000

$1 = 2\frac{3 - d}{\sqrt{(3 - d)^2 + 4}}$

$\sqrt{(3 - d)^2 + 4} = 6 - 2d$

From here we can square up both sides

$(3 - d)^2 + 4 = (6 - 2d)^2$

$9 - 6d + d^2 + 4 = 36 - 24d + 4d^2$

$3d^2-18d+27 = 0$

$d^2 - 6d + 9 = 0$

$(d - 3)^2 = 0$

$d -3 = 0$

d = 3

So the cost of pipeline is minimum when P is exactly 3km east from the oil refinery.

3 0

3 years ago

The force of gravity on an object varies directly with its mass. The constant of variation due to gravity is 32.2 feet per secon

castortr0y [4]

Answer:

Step-by-step explanation:

According to newton second law, the force of gravity on an object varies directly with its mass and it is expressed mathematically as Fαm i.e

F = mg where;

F is the force of gravity

m is the mass of the body

g is the proportionality constant known as the acceleration due to gravity.

If the constant of variation due to gravity is 32.2ft/s², the equation that represents F, the force on an object due to gravity according to m, the object’s mass can be gotten by substituting g = 32.2 into the formula above according to the law as shown;

F = m*32.2

F =32.2m

Hence the required equation is F = 32.2m

5 0

3 years ago

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