Question

find the value of k ,if (x+3)is a factor of p(x) and p (x) = kx^3+x^2-22x-21

Answer 1

X+3=0
x=-3
Kx^3+x^2-22x-21 =0
K (-3)^3+(-3)^2-22 (-3)-21=0
-27k +9 +66-21=0
-27k+75-21=0
-27k +54=0
-27k =-54
K=2

Answer 2

The value of k = 2

Step-by-step explanation:

We have,

(x + 3) is a factor of p(x):$kx^3+x^2-22x-21$

To find, the value of k = ?

∴ x + 3 = 0

⇒ x = - 3

Put x = - 3 is p(x), we get

∴ p(x) = 0

$p(-3):k(-3)^3+(-3)^2-22(-3)-21=0$

⇒ $-27k+9+66-21=0$

⇒ $-27k+75-21=0$

⇒ $-27k+54=0$

⇒ 27k = 54

⇒ k = 2

Hence, the value of k = 2