|4-2x| = x+5
\(\Leftrightarrow\left\{{}\begin{matrix}4-2x=x+5khi4-2x\ge0\\2x-4=x+5khi4-2x< 0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}-2x-x=5-4khi2x\ge-4\\2x-x=4+5khi2x< -4\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}-3x=1khix\ge-2\\x=9khix< -2\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{-1}{3}khix\ge-2\left(1\right)\\x=9khix< -2\left(2\right)\end{matrix}\right.\)
Trường hợp (1) thỏa mãn, trường hợp (2) không thỏa mãn
Vậy S = {\(\dfrac{-1}{3}\)}
/4-2x/=x+5
*TH1: 4-2x≥0 khi x≤-2
PT⇔4-2x=x+5⇔-3x=1⇔x=\(-\dfrac{1}{3}\) (ko tm)
*TH2: 4-2x<0 khi x>-2
PT⇔-4+2x=x+5⇔x=9(tm)
Vậy pt có tâp nghiệm S={9}
