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`2x-15 = 17``
`=> 2x = 17 + 15`
`=> 2x = 32`
`=> X = 32 : 2`
`=> x = 16`
`156 - (x + 61) = 82`
`=> x + 61 = 156 - 82`
`=> x + 61 = 74`
`=> x = 13`
`2x - 138 = 2^3 . 3^2`
`=>2x - 138 = 72`
`=> 2x = 210`
`=> x = 105`
bài 2:
`23-3x = 8`
`=> 3x = 23 - 8`
`=> 3x = 15`
`=> x = 5`
`(x-35) - 120 = 0`
`=>(x-35) = 120`
`=> x = 120 +35`
`=> x = 155`
`3^x + 2 = 29`
`=> 3^x = 27`
`=> 3^x = 3^3`
`=> x = 3`
b: \(\Leftrightarrow x+8\in\left\{1;-1;5;-5\right\}\)
hay \(x\in\left\{-7;-9;-3;-13\right\}\)
a: =>1/3x-2/5x=5
=>-1/15x=5
=>x=-75
b: =>4x=4
=>x=1
c: =>6*3^x-5*3^x=243
=>3^x=243
=>x=5
\(a,3x-31=-40\Rightarrow3x=-9\Rightarrow x=-3\)
\(b,-3x+37=\left(-4\right)^2\Rightarrow-3x=-21\Rightarrow x=7\)
\(c,\left|2x+7\right|=5\)
\(\Rightarrow\left\{{}\begin{matrix}2x+7=5\Rightarrow x=-1\\2x+7=-5\Rightarrow x=-6\end{matrix}\right.\)
\(d,-x+21=15+2x\Rightarrow3x=6\Rightarrow x=2\)
a) Ta có: 3x-31=-40
\(\Leftrightarrow3x=-9\)
hay x=-3
Vậy: x=-3
b) Ta có: \(-3x+37=\left(-4\right)^2\)
\(\Leftrightarrow-3x+37=16\)
\(\Leftrightarrow-3x=16-37=-21\)
hay x=7
Vậy: x=7
1) 3x = 45 + 15 = 60
x = 60 : 3 = 20
2) 5x = 50 - 35 = 15
x = 15 : 5 = 3
3) (2x - 5) + 17 = 6
2x - 5 = 6 - 17
2x - 5 = -11
2x = -11 + 5
2x = -6
x = -6 : 2 = -3
4) 10 - 2(4 -3x) = -4
2(4 - 3x) = -4 - 10 = -14
4 - 3x = -14 : 2 = -7
3x = -7 - 4 = -18
x = -18 : 3 = -6
\(35-3^{x+1}=8\)
\(\Rightarrow3^{x+1}=35-8=27\)
Mà \(27=3^3\)
\(\Rightarrow x+1=3\Rightarrow x=3-1=2\)
Vậy \(x=2\)
\(a.35-3^{x+1}=8\)
\(3^x.3^1=35-8\)
\(3^x.3^1=27\)
\(3^x.3^1=3^3\)
\(3^x=3^3:3^1\)
\(3^x=3^{3-1}\)
\(3^x=3^2\)
\(\Rightarrow x=2\)
\(b.3.2^{x-1}+5=29\)
\(3.2^x:2^1=29-5\)
\(3.2^x:2^1=24\)
\(2^x:2^1=24:3\)
\(2^x:2^1=8\)
\(2^x:2^1=2^3\)
\(2^x=2^3.2^1\)
\(2^x=2^{3+1}\)
\(2^x=2^4\)
\(\Rightarrow x=4\)
\(c.9:3^x+15=18\)
\(3^2:3^x+15=18-15\)
\(3^2:3^x=3\)
\(3^x=3^2:3\)
\(3^x=3^{2-1}\)
\(3^x=3^1\)
\(\Rightarrow x=1\)
Chúc bạn học tốt!