1. 72-3.|x+1|=9
3.|x+1|=63
|x+1|=21
=> x+1 = 21 hoặc x+1=-21
=> x=20 hoặc x=-22.
2. 17-(43-|x|)=45
43 - |x|=-28
|x| = 71.
=> x=71 hoặc x=-71
1) \(72-3.\left|x+1\right|=9\)
\(3.\left|x+1\right|=72-9\)
\(3.\left|x+1\right|=63\)
\(\left|x+1\right|=63:3\)
\(\left|x+1\right|=21\)
\(=>x+1=21\) hoặc \(x+1=-21\)
+) \(x+1=21\) +) \(x+1=-21\)
\(x=21-1\) \(x=\left(-21\right)-1\)
\(x=20\) \(x=-22\)
Vậy x thuộc {20; -22 }
2) \(17-\left(43-\left|x\right|\right)=45\)
\(43-\left|x\right|=17-45\)
\(43-\left|x\right|=-28\)
\(\left|x\right|=43-\left(-28\right)\)
\(\left|x\right|=71\)
\(=>x=71\) hoặc \(x=-71\)
Vậy x thuộc {71; -71 }
1,
72 - 3 . |x + 1| = 9
\(\Rightarrow\) 3 . |x + 1| = 72 - 9
\(\Rightarrow\) 3 . |x + 1| = 63
\(\Rightarrow\) |x + 1| = 63 : 3 \(\Rightarrow\) |x + 1| = 21 \(\Rightarrow\left[\begin{matrix}x+1=21\\x+1=-21\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=21-1\\x=-21-1\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=20\\x=-22\end{matrix}\right.\) Vậy: x \(\in\) {-22; 20} 2, 17 - (43 - |x|) = 45 \(\Rightarrow\) 43 - |x| = 17 - 45 \(\Rightarrow\) 43 - |x| = -28 \(\Rightarrow\) |x| = 43 - (-28) \(\Rightarrow\) |x| = 71 \(\Rightarrow\left[\begin{matrix}x=71\\x=-71\end{matrix}\right.\) Vậy: x \(\in\) {-71; 71}
2\(1.72-3.\left|x+1\right|=9\)
\(3.\left|x+1\right|=63\)
\(\left|x+1\right|=21\)
\(\Rightarrow x+1=21\)
hoặc \(x+1=-21\)
\(\Rightarrow x=20\)
hoặc x=-22
2.17-(43-|x|)=45
43 - |x| =-28
|x| = 71
\(\Rightarrow\) x=71 hoặc x = -71
