ziết như câu hỏi
=> (x-4)(1+3x+1)=0
=.(x+4)(3x+2)=0
=>\(\orbr{\begin{cases}x-4=0\\3x+2=0\end{cases}=>\orbr{\begin{cases}x=4\\x=\frac{2}{3}\end{cases}}}\)
\(\left(x-4\right)+\left(x-4\right).\left(3x+1\right)=0\)
\(\Leftrightarrow\left(x-4\right)\left(1+3x+1\right)=0\)
\(\Leftrightarrow\left(x+4\right)\left(3x+2\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x-4=0\\3x+2=0\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=4\\x=\frac{2}{3}\end{cases}}\)
Vậy x = 4 hoặc x = 2/3
