Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a) <=> 15-5x-20=-12-3
<=> -5x=-12-3-15+20=-10
=>x=-10:(-5)=2
b)<=>7-x-25-7=-25
<=> -x=-25-7+25+7=0 =>x=0
c) /x+2/=0 => x+2=0 =>x=-2
d) sai đề
e)<=> /x-5/ = 7
<=> \(\orbr{\begin{cases}x-5=7\\x-5=-7\end{cases}}\)
<=> \(\orbr{\begin{cases}x=12\\x=-2\end{cases}}\)
g) <=> -x-20-8+2x=-15
<=> x=-15+20+8=13
a) \(-5\left(-x+7\right)-3\left(-x-5\right)=-4\left(12-x\right)+48\)
\(\Leftrightarrow5x-35+3x+15=-48+4x+48\)
\(\Leftrightarrow4x=20\)
\(\Rightarrow x=5\)
b) \(-2\left(15-3x\right)-4\left(-7x+8\right)=-5-9\left(-2x+1\right)\)
\(\Leftrightarrow-30+6x+28x-32=-5+18x-9\)
\(\Leftrightarrow16x=48\)
\(\Rightarrow x=3\)
c) \(7\left(-x-7\right)-5\left(-x-3\right)=12\left(3-x\right)\)
\(\Leftrightarrow-7x-49+5x+15=36-12x\)
\(\Leftrightarrow10x=70\)
\(\Rightarrow x=7\)
d) \(5\left(-3x-7\right)-4\left(-2x-11\right)=7\left(4x+10\right)+9\)
\(\Leftrightarrow-15x-35+8x+44=28x+70+9\)
\(\Leftrightarrow35x=-70\)
\(\Rightarrow x=-2\)
e) \(-2\left(x+3\right)-15=3\left(4+2x\right)+7\)
\(\Leftrightarrow-2x-6-15=12+6x+7\)
\(\Leftrightarrow8x=-40\)
\(\Rightarrow x=-5\)
\(-3+x=5-\left(-7\right)\)
\(\Leftrightarrow-3+x=5+7\)
\(\Leftrightarrow-3+x=12\)
\(\Leftrightarrow x=12+3\)
\(\Leftrightarrow x=15\)
Vậy x= 15
\(x-2=2x-7\)
\(\Leftrightarrow x-2+7=2x\)
\(\Leftrightarrow x-\left(2-7\right)=2x\)
\(\Leftrightarrow2-7=x-2x\)
\(\Leftrightarrow-5=-x\)
\(\Leftrightarrow x=5\)
Vậy x= 5
1) |x + 2| = 4
\(\Leftrightarrow\orbr{\begin{cases}x+2=4\\x+2=-4\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=2\\x=-6\end{cases}}\)
2) 3 – |2x + 1| = (-5)
\(\Leftrightarrow\left|2x+1\right|=8\Leftrightarrow\orbr{\begin{cases}2x+1=8\\2x+1=-8\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=\frac{7}{2}\\x=\frac{-9}{2}\end{cases}}\)
3) 12 + |3 – x| = 9
\(\Leftrightarrow\left|3-x\right|=-3\)(vô lí)
=>\(x=\varnothing\)
1) I x+2 I=4
\(\Rightarrow\orbr{\begin{cases}x+2=4\\x+2=-4\end{cases}\Leftrightarrow\orbr{\begin{cases}x=2\\x=-6\end{cases}}}\)
2) \(3-|2x+1|=-5\)
\(\Leftrightarrow|2x+1|=8\)
\(\Leftrightarrow\orbr{\begin{cases}2x+1=8\\2x+1=-8\end{cases}\Leftrightarrow\orbr{\begin{cases}2x=7\\2x=-9\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=\frac{7}{2}\\x=\frac{-9}{2}\end{cases}}}\)
3) \(12+|3-x|=9\)
\(\Leftrightarrow|3-x|=-3\)(vô lí vì I 3-x I \(\ge\)0)
b: =>x(8-7)=-33
=>x=-33
c: =>-12x+60+21-7x=5
=>-19x=-76
hay x=4
d: =>-2x-2-x+5+2x=0
=>3-x=0
hay x=3