a: 3x- l2-5xl =4

Đáp án:

Giải thích các bước giải:

a) 3x- l2-5xl =4

⇔ l2-5xl = 4 – 3x

⇔\(\left[ \begin{array}{l}2-5x=4-3x\\2-5x=-4+3x\end{array} \right.\) 

⇔\(\left[ \begin{array}{l}-2x=2\\8x=6\end{array} \right.\) 

⇔\(\left[ \begin{array}{l}x=-1\\x=\frac{6}{8} \end{array} \right.\) 

b) l2x+3l-3x=1

⇔ l2x+3l=1+3x

⇔\(\left[ \begin{array}{l}2x+3=1+3x\\2x+3=-1-3x\end{array} \right.\) 

⇔\(\left[ \begin{array}{l}-x=-2\\5x=2\end{array} \right.\) 

⇔\(\left[ \begin{array}{l}x=2\\x=\frac{2}{5}\end{array} \right.\)