Question

Verify whether $2$ is a zero of the polynomial $x^3+4x^2-3x-18$ or not?

Answer 1

Let,

$f\left(x\right)=x^3+4x^2-3x-18$

If $2$ is a zero, then $f\left(2\right)$ must be equal to $0.$

So,

$f\left(2\right)=2^3+4(2{)}^2-3(2)-18$

$=8+16-6-18$

$=24-24$

$=0$

Hence, $2$ is a zero of the polynomial.