Question

Find the value of k if (-2) is the zero of the polynomial p(x) =2x^4 + 6x^3 + kx^2 − x + 2.

Answer 1

Answer:

2x^4 + 6x^3 + kx^2 - x + 2

2 × ( -2 )^4 + 6 × ( -2 )^3 + k × ( -2 )^2 - ( -2 ) + 2

2 × 16 + 6 × ( -8 ) + k × 4 + 2 + 2

32 - 48 + 4k + 4

36 - 48 + 4k

-12 + 4k

4k = 12

k = 3

Answer 2

Answer:

k =(-12)

Step-by-step explanation:

p(x)=2x^4+6x^3+kx^2-x+2

p(-2)= 2 (-2)^4 + 6 (-2)^3 -k (-2)^2 - (-2) +2

p(-2)= 32 + (-48) -k (4) + 4

p(2) = -12 + -4k

k = (-3)