a: =>31-x=60

=>x=-29

b: =>(x-140):35=280-270=10

=>x-140=350

=>x=490

c: =>(1900-2x):35=48

=>1900-2x=1680

=>2x=220

=>x=110

d: =>\(2^{2x-1}=2^9\cdot2=2^{11}\)

=>2x-1=11

=>x=6

e: =>(x+2)^5=4^5

=>x+2=4

=>x=2

f: =>3x-4=0 hoặc x-1=0

=>x=4/3 hoặc x=1

g: =>(2x-1)^2=49

=>2x-1=7 hoặc 2x-1=-7

=>x=-3 hoặc x=4

h: =>x(x+1)/2=78

=>x(x+1)=156

=>x=12

\(a,3\left(x+1\right)-2=4\)

\(\Leftrightarrow3\left(x+1\right)=6\)

\(\Leftrightarrow x+1=2\)

\(\Leftrightarrow x=1\)

Vậy x=1

Các câu còn lại lm tương tự nhé

\(3\left(x+1\right)-2=4\)

<=> \(3x+3-2=4\)

<=> \(3x=3\)

<=> \(x=1\)

\(5\left(x-2\right)+20=45\)

<=> \(5x-10=25\)

<=> \(x=7\)

\(700-7\left(x+2\right)=140\)

<=> \(7x+14=560\)

<=> \(7x=546\)

<=> \(x=78\)

\(200-5\left(2x+4\right)=100\)

<=> \(10x+20=100\)

<=> \(x=8\)

\(5\left(2x-4\right)+150=250\)

<=> \(10x-20=100\)

<=> \(x=12\)

học tốt

a) 3x - 4 (2x-7) = 3x - 3

3x - 8x + 28 = 3x - 3

=> 3x - 8x - 3x = -3 -28

-8x = -31

x =  31/8

b) 3(2x-7) - (4-2x) = 2x -1

6x - 7 - 4 + 2x = 2x -1

=> 6x + 2x - 2x = -1 + 7+4

6x  = 10

x = 5/3

c) (x-2).(2x+12)=0

=> x -2 = 0 => x = 2

2x + 12 = 0 => 2x = -12 => x = -6

KL: x = 2 hoặc x = -6

\(3x-4\left(2x-7\right)=3x-3\)

\(\Leftrightarrow3x-8x+28=3x-3\)

\(\Rightarrow3x-8x-3x=-3-28\)

\(\Leftrightarrow-8x=-31\)

\(\Leftrightarrow x=\frac{31}{8}\)

Mấy câu kia dễ đổi dấu tự làm :)

a)

`(1/2+2x)(2x-3)=0`

\(=>\left[{}\begin{matrix}\dfrac{1}{2}+2x=0\\2x-3=0\end{matrix}\right.\\ =>\left[{}\begin{matrix}2x=-\dfrac{1}{2}\\2x=3\end{matrix}\right.\\ =>\left[{}\begin{matrix}x=-\dfrac{1}{4}\\x=\dfrac{3}{2}\end{matrix}\right.\)

b)

`1/4-(2x+1/2)^2=0`

`=>(2x+1/2)^2=1/4`

\(=>\left[{}\begin{matrix}2x+\dfrac{1}{2}=\dfrac{1}{2}\\2x+\dfrac{1}{2}=-\dfrac{1}{2}\end{matrix}\right.\\ =>\left[{}\begin{matrix}2x=0\\2x=-1\end{matrix}\right.\\ =>\left[{}\begin{matrix}x=0\\x=-\dfrac{1}{2}\end{matrix}\right.\)

- Mình có thể giúp bài 1 :)

 5^x +  5^ ( x + 2 ) = 650

5^x +  5^x . 5² = 650

 5^x .( 1 + 25 ) = 650

 5^x . 26 = 650 

5^x = 650 : 26

 5^x = 25

 5^x = 5² 

=> x = 2 

Vậy x = 2 

137+4 (2x+3)=200(hình như đề bài sai)

200-6(x-5)=140

        6(x-5)=200-140

        6(x-5)=60

           x-5=60:6

           x-5=10

              x=10+5

              x=15

140:(x-8)=7

        x-8=140:7

        x-8=20

         x=20+8

         x=28

137+4(2x+3)=200

4(2x+3)=200-137

4(2x+3)=63

2x+3=63:4

2x+3=\(\frac{63}{4}\)

2x=\(\frac{63}{4}\)-3

2x=\(\frac{51}{4}\)

x=\(\frac{51}{4}\):2

x=\(\frac{51}{8}\)

Vậy ...

200-6(x-5)=140

6(x-5)=200-140

6(x-5)=60

x-5=60:6

x-5=10

x=15

Vậy...

140:(x-8)=7

x-8=140:7

x-8=20

x=20+8

x=28

Vậy...

k mik nhé

Bài 2: 

a: Ta có: \(2^{x+1}\cdot3^y=12^x\)

\(\Leftrightarrow2^{x+1}\cdot3^y=2^{2x}\cdot3^x\)

\(\Leftrightarrow\left\{{}\begin{matrix}x+1=2x\\x=y\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=1\\y=1\end{matrix}\right.\)