a) Ta có:  x 2 = 2 2  nên x = 2.

b) Ta có: x 2 = 5 2 nên x = 5.

c) Ta có:  3 x 5 = 3  nên  x 5 = 1 . Do đó x = 1.

d) Ta có:  6 x 3 = 48  nên  x 3 = 8 . Do đó x = 2.

e) Ta có:  x - 1 2 = 2 2  nên  x - 1 = 2 . Do đó x = 3.

f) Ta có:  x + 1 2 = 5 2  nên x +1 = 5. Do đó x = 4.

g) Ta có:  x - 1 3 = 3 3  nên  x - 1 = 3 . Do đó x = 4.

h) Ta có:  x + 1 3 = 4 3 nên x +1 = 4. Do đó x = 3

\(a.\dfrac{12+x}{42}=\dfrac{35}{42}\Leftrightarrow12+x=35\Leftrightarrow x=23\)

\(b.\dfrac{25-x}{40}=\dfrac{3}{8}\Leftrightarrow\dfrac{25-x}{40}=\dfrac{15}{40}\Leftrightarrow25-x=15\Leftrightarrow x=10\)

\(c.\dfrac{13+x}{20}=\dfrac{3}{4}\Leftrightarrow\dfrac{13+x}{20}=\dfrac{15}{20}\Leftrightarrow13+x=15\Leftrightarrow x=2\)

\(d.\dfrac{23-x}{25}=\dfrac{20}{25}\Leftrightarrow23-x=20\Leftrightarrow x=3\)

a) 22 + (2x -13) = 83 => 2x -13 = 61 => x = 37.

b) 51 - (-12 + 3x) = 27 => 63 - 3x = 27 => x = 12.

c) - (2x + 2) + 21 = - 23 => 2x + 2 = 44 => x = 21.

d) 25 - (25 - x) = 0 => 25 - 25 + x = 0 => x = 0.

a, 11 - ( 15 + 11 ) = x - ( 25 - 9 )

11-15-11=x-25+9

-15=x-16

x=1

b, 2 - x = 17 - ( - 5 )

2-x=22

x=-20

c, x - 12 = ( - 9 ) - 15

x-12=-24

x=-12

d, 9 - 25 = ( 7 - x ) - ( 25 + 7 )

(7-x)-32=-16

7-x=16

x=-9

#H

a) 15 – ( 4 – x) = 6 

=>  4 – x= 15 - 6

=>  4 – x= 9

=>  x= 4 - 9 

=>  x= -5

Easy!

a) \(15-\left(4-x\right)=6\)

\(\Leftrightarrow4-x=15-6\)

\(\Leftrightarrow4-x=9\)

\(\Leftrightarrow x=4-9\)

\(\Leftrightarrow x=-5\)

Vậy \(x=-5\)

b) \(-30+\left(25-x\right)=-1\)

\(\Leftrightarrow\left(25-x\right)=-1-\left(-30\right)\)

\(\Leftrightarrow25-x=29\)

\(\Leftrightarrow x=25-29\)

\(\Leftrightarrow x=-4\)

c) \(x-\left(12-25\right)=-8\)

\(\Leftrightarrow x-\left(-13\right)=-8\)

\(\Leftrightarrow x=-8+-13\)

\(\Leftrightarrow x=-21\)

Vậy \(x=-21\)

d) \(\left(x-29\right)-\left(17-38\right)=-9\)

\(\Leftrightarrow\left(x-29\right)-\left(-21\right)=-9\)

\(\Leftrightarrow x-29=-9+\left(-21\right)\)

\(\Leftrightarrow x-29=-30\)

\(\Leftrightarrow x=-30+29\)

\(\Leftrightarrow x=-1\)

Vậy \(x=-1\)

\(a.15-\left(4-x\right)=6\)

\(4-x=15-6\)

\(4-x=9\)

\(x=4-9\)

\(x=-5\)

Vậy \(x\in\left\{-5\right\}\)

\(b.-30+\left(25-x\right)=-1\)

\(25-x=-1-\left(-30\right)\)

\(25-x=29\)

\(x=25-29\)

\(x=-4\)

Vậy \(x\in\left\{-4\right\}\)

\(c.x-\left(12-25\right)=-8\)

\(x-\left(-13\right)=-8\)

\(x=-8+\left(-13\right)\)

\(x=-21\)

Vậy \(x\in\left\{-21\right\}\)

\(d.\left(x-29\right)-\left(17-38\right)=-9\)

\(\left(x-29\right)-\left(-21\right)=-9\)

\(x-29=-9+\left(-21\right)\)

\(x-29=-30\)

\(x=-30+29\)

\(x=-1\)

Vậy \(x\in\left\{-1\right\}\)

a: =>25-4x=1

=>4x=24

hay x=6

b: =>2x-4=0

hay x=2

c: =>x-35=115

hay x=150

d: =>x-2=12

hay x=14

e: =>x-36=216

hay x=252

a) x = 15

b) x = 11

c) x = 68

d) x = 310

(x4)3=x6x19