Question

Solve using factorization method: $7m^2-84=0$.

Answer 1

Given $7m^2-84=0$

Taking $7$ common from both terms, we get:

$7(m^2-12)=0$

$\Rightarrow 7(m^2-(\sqrt{12}{)}^2)=0$

We know that, $a^2-b^2=(a+b)(a-b)$

Hence, $7(m-\sqrt{12})(m+\sqrt{12})=0$

$\Rightarrow (m-\sqrt{12})=0$ or $(m+\sqrt{12})=0$

$\therefore m=-\sqrt{12}$ or $\sqrt{12}$

Hence, $m=\sqrt{12},-\sqrt{12}$ is the solution of the given equation.