If (x + 1) is factor of the polynomial
Question:

If $(x+1)$ is factor of the polynomial $\left(2 x^{2}+k x\right)$ then the value of $k$ is

(a) –2
(b) –3
(c) 2
(d) 3

Solution:

(c) 2

$(x+1)$ is a factor of $2 x^{2}+k x$

So, $-1$ is a zero of $2 x^{2}+k x$.

Thus, we have :

$2 \times(-1)^{2}+k \times(-1)=0$

$\Rightarrow 2-k=0$

$\Rightarrow k=2$