a, 2. \(\left|x-20\right|\)=10
\(\Leftrightarrow\)\(\left|x-20\right|\)=5
\(\Leftrightarrow\)\(\left[\begin{matrix}x-20=5\\x-20=-5\end{matrix}\right.\)
\(\Leftrightarrow\)\(\left[\begin{matrix}x=25\\x=15\end{matrix}\right.\)
Vậy ...
b,2. \(\left|x-5\right|\)=2\(^5\)
\(\Leftrightarrow\)2. \(\left|x-5\right|\)=32
\(\Leftrightarrow\)\(\left|x-5\right|\)=16
\(\Leftrightarrow\)\(\left[\begin{matrix}x-5=16\\x-5=-16\end{matrix}\right.\)
\(\Leftrightarrow\)\(\left[\begin{matrix}x=21\\x=-11\end{matrix}\right.\)
Vậy...
c,-5x+(7-15)=6x+5
\(\Leftrightarrow\)-5x-8-6x-5=0
\(\Leftrightarrow\)-11x-13=0
\(\Leftrightarrow\)-11x=13
\(\Leftrightarrow\)x=-\(\frac{13}{11}\)
Vậy...
d, 23-3. \(\left|2x+6\right|\)=-7
\(\Leftrightarrow\)3. \(\left|2x+6\right|\)=30
\(\Leftrightarrow\)\(\left|2x+6\right|\)=10
\(\Leftrightarrow\)\(\left[\begin{matrix}2x+6=10\\2x+6=-10\end{matrix}\right.\) \(\Leftrightarrow\)\(\left[\begin{matrix}x=2\\x=-8\end{matrix}\right.\)
Vậy...
\(2\left|x-20\right|=10\Leftrightarrow\left|x-20\right|=5\Leftrightarrow\left[\begin{matrix}x-20=5\\x-20=-5\end{matrix}\right.\Leftrightarrow\left[\begin{matrix}x=25\\x=15\end{matrix}\right.\)
Vậy\(x\in\left\{25;15\right\}\)
\(2.\left|x-5\right|=2^5\Leftrightarrow2.\left|x-5\right|=32\Leftrightarrow\left|x-5\right|=16\Leftrightarrow\left[\begin{matrix}x-5=16\\x-5=-16\end{matrix}\right.\)\(\Leftrightarrow\left[\begin{matrix}x=21\\x=-11\end{matrix}\right.\)Vậy\(x\in\left\{-11;21\right\}\)
a, 2.lx - 20l = 10
lx - 20l = 10 : 2
lx - 20l = 5
=> x - 20 = 5 hoặc x - 20 = -5
TH1: x - 20 = 5
x = 5 + 20
x = 25
TH2: x - 20 = -5
x = -5 + 20
x = 15
Vậy x = 15 hoặc x = 20
b, 2lx - 5l = \(^{2^5}\)
2lx - 5l = 32
lx - 5l = 32 : 2
lx - 5l = 16
=> x - 5 = 16 hoặc x - 5 = -16
TH1 : x - 5 = 16
x = 16 + 5
x = 21
TH2 : x - 5 = -16
x = -16 + 5
x = -11
Vậy x = -11 hoặc x = 21