ta có : \(\left(x-3\right)\left(x+4\right)-2\left(3x-2\right)=\left(x-4\right)^2\)
\(\Leftrightarrow x^2+4x-3x-12-6x+4=x^2-8x+16\)
\(\Leftrightarrow x^2+4x-3x-12-6x+4-x^2+8x-16=0\)\(\Leftrightarrow3x-24=0\Leftrightarrow x=\dfrac{24}{3}=8\) vậy \(x=8\)