Which expression is equal to f(x) · g(x)?

C. x⁴ + 6·x³ - 12·x  - 72

Explanation:

The given functions are;

g(x) = x³ -12

We have that = =  (x + 6)

Therefore;

f(x)·g(x) = × (x³ - 12) = (x + 6) × (x³ - 12)

(x + 6) × (x³ - 12) = x⁴ - 12·x + 6·x³ - 72 = x⁴ + 6·x³ - 12·x  - 72

∴ f(x)·g(x) = × (x³ - 12) = x⁴ + 6·x³ - 12·x  - 72