Answer
$\{-2,2\}$
Work Step by Step
Use distributive property.
$\begin{align*}
3x(x)+3x(2)&=6(x)+6(2)\\
3x^2+6x&=6x+12
\end{align*}$
Add $-6x-12$ to both sides.
$3x^2+6x-6x-12=6x+12-6x-12$
Simplify.
$3x^2-12=0$
Factor out $3$.
$3(x^2-4)=0$
$3(x^2-2^2)=0$
Use special formula $(a^2-b^2)=(a+b)(a-b)$ with $a=x$ and $b=2$ to obtain:
$3(x+2)(x-2)=0$
Use Zero-Product Property.
$x+2=0$ or $x-2=0$
Solve each equation for $x$.
$x=-2$ or $x=2$
Hence, the solution set of the equation is $\{-2,2\}$.
