Question

Find the value of k if 5 is zero of the polynomial x^3+kx^2+2x+8.

Answer 1

Answer:

if the question is correct, then the answer would be

k=-143/25 or -5.72

Step-by-step explanation:

let f(x)= x³+kx²+2x+8

if 5 is a zero of f(x)

then f(5)=0

f(5)= (5)³+k(5)²+2(5)+8

125+25k+10+8=0

143+25k=0

25k= -143

k= -143/25 or -5.72