Jika f'(x) = -6x² -8x – 1 dan f(-2) = 9, maka f(x)=…​

Integral

f(x) = ∫f'(x) dx

f(x) = ∫(-6x² – 8x – 1) dx

f(x) = -6/3 x³ – 8/2 x² – x + C

f(x) = -2x³ – 4x² – x + C

f(-2) = 9

-2(-2)³ – 4(-2)² – (-2) + C = 9

16 – 16 + 2 + C = 9

C = 7

f(x) = -2x³ – 4x² – x + 7