Đáp án:
Giải thích các bước giải:
a, |2x - 1|=15
⇔\(\left[ \begin{array}{l}2x-1=15\\2x-1=-15\end{array} \right.\)
⇔\(\left[ \begin{array}{l}2x=16\\2x=-14\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=8\\x=-7\end{array} \right.\)
Vậy x ∈ {8;-7}
b, 7x . ( 2 + x ) - 7x .( x + 3 )=14
⇔7x . (2 + x - x - 3)=14
⇔7x . -1=14
⇔7x =-14
⇔ x =(-2)
Vậy x=(-2)
c, ( x + 2 ) . ( x - 3)=0
⇔\(\left[ \begin{array}{l}x+2=0\\x-3=0\end{array} \right.\)
⇔\(\left[ \begin{array}{l}x=-2\\x=3\end{array} \right.\)
Vậy x ∈ {-2;3}