Question

If the value of the polynomial $m^3+2m+a$ is 12 for $m=2$ , then find the value of a.

Answer 1

Let $p\left(m\right)=m^3+2m+a$

For m = 2, p(2) = 12.

$$\begin{gathered} \therefore {\left(2\right)}^3+2\times 2+a=12 \\ \Rightarrow 8+4+a=12 \\ \Rightarrow 12+a=12 \\ \Rightarrow a=12-12=0 \end{gathered}$$
Thus, the value of a is 0.