Đáp án:
Giải thích các bước giải:
1)3x - 2(x-3) =6
⇔3x-2x+6=6
⇔x=-6+6
⇔x=0
Vậy S={0}
2) (x-1)² = 9(x+1)²
⇔(x-1)² = [3(x+1)]²
⇔(x-1)² = (3x+3)²
⇔(x-1)² - (3x+3)²=0
⇔(x-1-3x-3)(x-1+3x+3)=0
⇔(−2x−4)(4x+2)=0
⇔\(\left[ \begin{array}{l}-2x-4=0\\4x+2=0\end{array} \right.\)
⇔\(\left[ \begin{array}{l}-2x=4\\4x=-2\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=-2\\x=\frac{-1}{2} \end{array} \right.\)
Vậy S={-2;$\frac{-1}{2}$ }
