If (x + 5) is a factor of p(x)


If $(x+5)$ is a factor of $p(x)=x^{3}-20 x+5 k$, then $k=?$

(a) $-5$

(b) 5

(c) 3

(d) $-3$




(b) 5

$(x+5)$ is a factor of $p(x)=x^{3}-20 x+5 k$.

$\therefore p(-5)=0$

$\Rightarrow(-5)^{3}-20 \times(-5)+5 k=0$

$\Rightarrow-125+100+5 k=0$

$\Rightarrow 5 k=25$

$\Rightarrow k=5$


Leave a comment


Click here to get exam-ready with eSaral

For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.

Download Now