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