F(x)=x^3+3x^2-x-3. The expression f(x)÷(x-k) has a remainder of -15. what is the value of k?

Question

F(x)=x^3+3x^2-x-3. The expression f(x)÷(x-k) has a remainder of -15.

what is the value of k?

HELP PLEASE!!!!!! I NEED IT ASAP

Answer 1

f(x) = x²(x+3)-(x+3)

f(x) = (x²-1)(x+3) = (x+1)(x-1)(x+3)

if x=0, f(0) = -3

f(0)/(-k)=-15

k = -3/15 = -1/5