Easy ! do #13 and #14 (#15 optional) show work!

13. Let A = the amount of money in the given time, P = principal amount; the amount of money you start with, T = time in years, R = interest rate, and N = amount of times interest is compounded each year.

The formula for compound interest is:



Now, we find in the information from the description needed to plug in. P = $1000, R = 7% or 0.07, N = 1 time a year, T = 3 years



This simplifies to:



And again to:



Plug this into a calculator:

A = 1225.043 or ≈1,225.04

14. (x² + 3)(x - 3)(x + 3)

I'm going to do FOIL method on the second and third binomials first and simplify. This gives you:

(x² + 3)(x² - 9)

Then you do the FOIL method again to get:

x⁴ - 9x² + 3x² - 27

And combine like terms for your

x⁴ - 6x² - 27

Number 15 doesn't give you a number to set the polynomial (that results from multiplying those two binomials) equal to so I'm guessing it wants you to set said polynomial equal to zero and solve for x then plug back in. 

If not, your area is found by the equation 3x² - 5x - 12