Đáp án:
Giải thích các bước giải:
1/ |2x - 5| = x + 1
⇔\(\left[ \begin{array}{l}2x-5=x+1\\2x-5=-x-1\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=6\\3x=4\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=6\\x=3/4\end{array} \right.\)
Vậy x ∈ {6;3/4}
2/ |x - 1| = 2x + 1
⇔\(\left[ \begin{array}{l}x-1=2x+1\\x-1=-2x-1\end{array} \right.\)
⇔\(\left[ \begin{array}{l}-x=2\\3x=0\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=-2\\x=0\end{array} \right.\)
Vậy x ∈ {-2;0}
