Answer:
A) x^3-27
Step-by-step explanation:
start by multplying x to the numbers in the second set of parenthesis:
x^3+3x^2+9x
then multiply the -3 to the numbers in the second set of parenthesis:
-3x^2-9x-27
add these together:
(x^3+3x^2+9x) + (-3x^2-9x-27)
the 3x^2 and -3x^2 cancel as do the 9x and -9x so you are left with x^3-27