Question

If x+6 is a factor of p(x) equal to x3;+3x2+4x+k , find the value of k

Answer 1

Answer:

Let x+6=0

x= -6

Let (px) = 0

x³+3x²+4x+k =0

(-6)^3+3(-6)^2+4(-6)+k = 0

-216+108-24+k = 0

-134+k = 0

k = 134.

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Answer 2

Since (x + 6) is a factor of p(x), we can say that at x = -6, p(x) = 0

p(x) = x^3 + 3x^2 + 4x + k

p(-6) = (-6)^3 + 3(-6)^2 + 4(-6) + k = 0


(-216) + (108) - 24 + k = 0

k = 216 - 108 + 24 = 132

k = 132 —-> Answer