[tex]\bf \textit{difference of squares}
\\ \quad \\
(a-b)(a+b) = a^2-b^2\qquad \qquad
a^2-b^2 = (a-b)(a+b)\\\\
-------------------------------\\\\
4x^2-9=0\implies 2^2x^2-3^2=0\implies (2x)^2-3^2=0
\\\\\\\
[(2x)-3][(2x)+3]=0\implies
\begin{cases}
2x-3=0\\
2x=3\\
x=\frac{3}{2}\\
------\\
2x+3=0\\
2x=-3\\
x=-\frac{3}{2}
\end{cases}[/tex]
