À tính nhầm tí TH2 \(\Leftrightarrow x=-17\) không nhìn kỹ :D
|x - 3| - 7 = 13
<=> |x - 3| = 13 + 7
<=> |x - 3| = 20
<=> x - 3 = \(\pm\)20
\(\Rightarrow\left[{}\begin{matrix}x-3=20\\x-3=-20\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=20+3\\x=-20+3\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=23\\x=-17\end{matrix}\right.\)
Vậy x = 23 hoặc x = -17.
\(\left|x-3\right|-7=13\) ( 1 )
+ ) \(\left|x-3\right|=x-3.\)Khi \(x-3\ge0\Leftrightarrow x\ge3\)
\(\left(1\right)\Leftrightarrow x-3-7=13\)
\(\Leftrightarrow x=23\) ( thõa mãn )
+ ) \(\left|x-3\right|=-x+3.\)Khi \(x-3< 0\Leftrightarrow x< 3\)
\(\left(x\right)\Leftrightarrow-x+3-7=13\)
\(\Leftrightarrow x=-7\) ( thõa mãn )
Vậy................. :D
\(Gi\text{ải}\)
\(\left|x-3\right|-7=13\)
\(\rightarrow\) \(\left|x-3\right|=13+7\)
\(\rightarrow\left|x-3\right|=20\)
Có hai trường hợp
\(x-3=20\)
\(\rightarrow x=20+3\)
\(\rightarrow x=23\)
hoặc
\(x-3=-20\)
\(\rightarrow x=\left(-20\right)+3\)
\(\rightarrow x=-17\)
Vậy \(x=23\) hoặc \(x=-17\)
Ta có :
\(\left|x-3\right|-7=13\)
\(\left|x-3\right|=13+7\)
\(\left|x-3\right|=20\)
\(\Rightarrow\left[{}\begin{matrix}x-3=20\\x-3=-20\end{matrix}\right.\)
\(TH1:\)
\(x-3=20\)
\(x=20+3\)
\(x=23\)
\(TH2:\)
\(x-3=-20\)
\(x=\left(-20\right)+3\)
\(x=-17\)
Vậy \(x\in\left\{23;-17\right\}\) là giá trị cần tìm