a. -12(x-5)+7(3-x)=5 b. 30(x+2)-6(x-5)-24x=10 c. 7x-1+3x-2=-23
⇔-12x+60+21-7x=5 ⇔30x+60-6x+30-24x=10 ⇔10x-3=-23
⇔-12x-7x=5-60-21 ⇔0x=-80 ⇔10x=-20
⇔x=$\frac{-76}{-19}$ phương trình vô nghiệm ⇔x=-2
⇔x=4
h. 4x-5-6x+7=-18 a. IxI=17-3
⇔-2x=-20 ⇔\(\left[ \begin{array}{l}x=4\\x=-4\end{array} \right.\)
⇔x=10
c. Ix-1I=10
⇔\(\left[ \begin{array}{l}x-1=10\\x-1=-10\end{array} \right.\) Ix-1I=10
⇔\(\left[ \begin{array}{l}x=11\\x=-10\end{array} \right.\)
d. I2x-5I=13
⇔\(\left[ \begin{array}{l}2x-5=13\\2x-5=-13\end{array} \right.\) \(\left[ \begin{array}{l}x=9\\x=-4\end{array} \right.\)
⇔
