*) (x+7)(x-4)=2(x-4)
<=> (x+7)(x-4)=2(x-4)
<=> (x+7)(x-4)-2(x-4)=0
<=> (x-4)(x+7-2)=0
<=> (x-4)(x+5)=0
\(\Leftrightarrow\orbr{\begin{cases}x-4=0\\x+5=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=4\\x=-5\end{cases}}}\)
*) \(\left(3x-1\right)^2=16\)
\(\Leftrightarrow\orbr{\begin{cases}3x-1=4\\3x-1=-4\end{cases}\Leftrightarrow\orbr{\begin{cases}3x=5\\3x=-3\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{5}{3}\\x=-1\end{cases}}}}\)