Question

(2x+1)(2-3x)=9x²-4

Answer 1

\(\left(2x+1\right)\left(2-3x\right)=9x^2-4\)

\(\Leftrightarrow\left(-2x-1\right)\left(3x-2\right)-\left(9x^2-4\right)=0\)

=>\(\left(-2x-1\right)\left(3x-2\right)-\left(3x-2\right)\left(3x+2\right)=0\)

=>\(\left(3x-2\right)\left(-2x-1-3x-2\right)=0\)

=>(3x-2)(-5x-3)=0

=>(5x+3)(3x-2)=0

=>\(\left[{}\begin{matrix}5x+3=0\\3x-2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{3}{5}\\x=\dfrac{2}{3}\end{matrix}\right.\)