Answer:
(A) 6x³+8x² + 4x - 4, but only if my change is correct to 6x³5x² - 2 is correct.
Explanation:
Is "g(x) = 6x³5x² - 2" meant to be g(x) = 6x³-5x² - 2?
If so, (f+g)(x) = 3x² + 4x - 6 - (6x³-5x² - 2)
(f+g)(x) = 3x² + 4x - 6 - 6x³+5x² + 2
(f+g)(x) = 6x³+8x² + 4x - 4
(A)