\(\left|x-5\right|=7\)
\(\Rightarrow x-5=7\) hoặc \(x-5=-7\)
+) \(x-5=7\Rightarrow x=12\)
+) \(x-5=-7\Rightarrow x=-2\)
Vậy \(x\in\left\{12;-2\right\}\)
\(\left|x+1\right|=3\)
\(\Rightarrow x+1=3\) hoặc \(x+1=-3\)
+) \(x+1=3\Rightarrow x=2\)
+) \(x+1=-3\Rightarrow x=-4\)
Vậy \(x\in\left\{2;-4\right\}\)
+) |x - 5| = 7
\(\Rightarrow\) \(\left[\begin{matrix}x-5=7\\x-5=-7\end{matrix}\right.\)\(\Rightarrow\left[\begin{matrix}x=7+5\\x=-7+5\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=12\\x=-2\end{matrix}\right.\)
Vậy: x \(\in\) {-2; 12}
+) |x + 1| = 3
\(\Rightarrow\left[\begin{matrix}x+1=-3\\x+1=3\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=-3-1\\x=3-1\end{matrix}\right.\Rightarrow\left[\begin{matrix}x=-4\\x=2\end{matrix}\right.\)
Vậy: x \(\in\) {-4; 2}
\(\left|x-5\right|=7=\left|7\right|=\left|-7\right|\)
+) \(x-5=7\) +) \(x-5=-7\)
\(x=7+5\) \(x=\left(-7\right)+5\)
\(x=12\) \(x=-2\)
\(\left|x+1\right|=3=\left|3\right|=\left|-3\right|\)
+) \(x+1=3\) +) \(x+1=-3\)
\(x=3-1\) \(x=\left(-3\right)-1\)
\(x=2\) \(x=-4\)
