a) 72 - 3.|x+1| = 9
=> 3.|x+1| = 63
=> |x+1| = 21 => \(\left[{}\begin{matrix}x+1=21\\x+1=-21\end{matrix}\right.=>\left[{}\begin{matrix}x=20\\x=-22\end{matrix}\right.\)
b) 17 - (43 - |x|) = 45
=> 43 - |x| = -28
=> |x| = 71 => \(\left[{}\begin{matrix}x=71\\x=-71\end{matrix}\right.\)
c) 3|x-1|-5=7
=> 3|x-1|=12
=> |x-1| = 4 => \(\left[{}\begin{matrix}x-1=4\\x-1=-4\end{matrix}\right.=>\left[{}\begin{matrix}x=5\\x=-3\end{matrix}\right.\)
Chúc bn học tốt
a) \(72-3\cdot\left|x+1\right|=9\)
\(3\cdot\left|x+1\right|=72-9\)
\(3\cdot\left|x+1\right|=63\)
\(\left|x+1\right|=\dfrac{63}{3}\)
\(\left|x+1\right|=21\)
\(\circledast\)TH1: x+1=21
x=21-1
x=20
\(\circledast\)TH2: x+1=-21
x=-21-1
x=-22
Vậy \(x\in\left\{-22;20\right\}\).
b) \(17-\left(43-\left|x\right|\right)=45\\
17-43+\left|x\right|=45\\
-26+\left|x\right|=45\\
\left|x\right|=45-\left(-26\right)\\
\left|x\right|=71\)
x=71 hoặc x=-71
Vậy \(x\in\left\{-71;71\right\}\).
c) \(3\left|x-1\right|-5=7\\ 3\left|x-1\right|=7+5\\ 3\left|x-1\right|=12\\ \left|x-1\right|=\dfrac{12}{3}\\ \left|x-1\right|=4\)
\(\circledast\)TH1: x-1=4
x=4+1
x=5
\(\circledast\)TH2: x-1=-4
x=-4+1
x=-3
Vậy \(x\in\left\{-3;5\right\}\).
