\(a)x=\dfrac{1}{4}+\dfrac{5}{13}=\dfrac{33}{52}.\\ b)\dfrac{x}{3}=\dfrac{2}{3}+\dfrac{-1}{7}.\\ \Leftrightarrow\dfrac{x}{3}=\dfrac{11}{21}.\\ \Leftrightarrow\dfrac{7x}{21}=\dfrac{11}{21}.\\ \Rightarrow7x=11.\\ \Leftrightarrow x=\dfrac{11}{7}.\\ c)\dfrac{x}{3}=\dfrac{16}{24}+\dfrac{24}{36}=\dfrac{2}{3}+\dfrac{2}{3}=\dfrac{4}{3}.\\ \Rightarrow x=4.\\ d)\dfrac{x}{15}=\dfrac{1}{5}+\dfrac{2}{3}=\dfrac{13}{15}.\\ \Rightarrow x=13.\)

a: 2x(x+1)-135=-200

=>2(x^2+x)=-65

=>2x^2+2x+65=0

=>x^2+x+32,5=0

=>x^2+x+0,25+32,25=0

=>(x+0,5)^2+32,25=0(vô lý)

b: 4x-5(x-1)+15=13

=>4x-5x+5=-2

=>5-x=-2

=>x=5+2=7

c: 2/3x-1/4=3/5-7/8

=>2/3x=3/5-7/8+1/4=24/40-35/40+10/40=-1/40

=>x=-1/40:2/3=-1/40*3/2=-3/80

d: 1/2(2x-3)+105/2=-137/2

=>1/2(2x-3)=-137/2-105/2=-242/2=-121

=>2x-3=-242

=>2x=-239

=>x=-239/2

a) x × 5 = 50 – 15

x × 5 = 35

x = 35 : 5

x = 7

b) x : 4 = 38 – 33

x : 4 = 5

x = 5 × 4

x = 20

c) x + 356 = 414 + 62

x + 356 = 476

x = 476 – 356

x = 120

d) x : 4 = 2 × 3

x : 4 = 6

x = 6 × 4

x = 24

Chọn A

a) 5.2² + (x + 3) = 5²

5.4 + x + 3 = 25

20 + x + 3 = 25

x + 23 = 25

x = 25 - 23

x = 2

b) 2³ + (x - 3²) = 5³ - 4³

8 + (x - 9) = 125 - 64

8 + x - 9 = 61

x - 1 = 61

x = 61 + 1

x = 62

c) 4.(x - 5) - 2³ = 2⁴.3

4x - 20 - 8 = 16.3

4x - 28 = 48

4x = 48 + 28

4x = 76

x = 76 : 4

x = 19

d) 5.(x + 7) - 10 = 2³.5

5x + 35 - 10 = 8.5

5x + 25 = 40

5x = 40 - 25

5x = 15

x = 15 : 5

x = 3

e) 7² - 7.(13 - x) = 14

49 - 91 + 7x = 14

7x - 42 = 14

7x = 14 + 42

7x = 56

x = 56 : 7

x = 8

a) \(5\cdot2^2+\left(x+3\right)=5^2\)

\(\Rightarrow x+3=5^2-5\cdot2^2\)

\(\Rightarrow x+3=25-5\cdot4\)

\(\Rightarrow x+3=5\)

\(\Rightarrow x=5-3\)

\(\Rightarrow x=2\)

b) \(2^3+\left(x-3^2\right)=5^3-4^3\)

\(\Rightarrow8+\left(x-9\right)=125-64\)

\(\Rightarrow8+x-9=61\)

\(\Rightarrow x-1=61\)

\(\Rightarrow x=61+1\)

\(\Rightarrow x=62\)

c) \(4\left(x-5\right)-2^3=2^4\cdot3\)

\(\Rightarrow4\left(x-5\right)=2^4\cdot3+2^3\)

\(\Rightarrow4\cdot\left(x-5\right)=16\cdot3+8\)

\(\Rightarrow4\cdot\left(x-5\right)=56\)

\(\Rightarrow x-5=56:4\)

\(\Rightarrow x-5=14\)

\(\Rightarrow x=19\)

d) \(5\left(x+7\right)-10=2^3\cdot5\)

\(\Rightarrow5\left(x+7\right)=8\cdot5+10\)

\(\Rightarrow5\left(x+7\right)=40+10\)

\(\Rightarrow5\left(x+7\right)=50\)

\(\Rightarrow x+7=10\)

\(\Rightarrow x=10-7\)

\(\Rightarrow x=3\)

e) \(7^2-7\left(13-x\right)=14\)

\(\Rightarrow7\left(13-x\right)=7^2-14\)

\(\Rightarrow7\left(13-x\right)=49-14\)

\(\Rightarrow7\left(13-x\right)=35\)

\(\Rightarrow13-x=5\)

\(\Rightarrow x=13-5\)

\(\Rightarrow x=8\)

f) \(5x-5^2=10\)

\(\Rightarrow5x=10+5^2\)

\(\Rightarrow5x=10+25\)

\(\Rightarrow5x=35\)

\(\Rightarrow x=\dfrac{35}{5}\)

\(\Rightarrow x=7\)

g) \(9x-2\cdot3^2=3^4\)

\(\Rightarrow9x=3^4+2\cdot3^2\)

\(\Rightarrow9x=81+2\cdot9\)

\(\Rightarrow9x=99\)

\(\Rightarrow x=\dfrac{99}{9}\)

\(\Rightarrow x=11\)

h) \(10x+2^2\cdot5=10^2\)

\(\Rightarrow10x=10^2-2^2\cdot5\)

\(\Rightarrow10x=100-4\cdot5\)

\(\Rightarrow10x=80\)

\(\Rightarrow x=\dfrac{80}{10}\)

\(\Rightarrow x=8\)

i) \(125-5\left(4+x\right)=15\)

\(\Rightarrow5\left(4+x\right)=125-5\)

\(\Rightarrow5\left(4+x\right)=120\)

\(\Rightarrow4+x=\dfrac{120}{5}\)

\(\Rightarrow4+x=24\)

\(\Rightarrow x=24-4\)

\(\Rightarrow x=20\)

j) \(2^6+\left(5+x\right)=3^4\)

\(\Rightarrow5+x=3^4-2^6\)

\(\Rightarrow5+x=81-64\)

\(\Rightarrow5+x=17\)

\(\Rightarrow x=17-5\)

\(\Rightarrow x=12\)

f) 5x - 5² = 10

5x - 25 = 10

5x = 10 + 25

5x = 35

x = 35 : 5

x = 7

g) 9x - 2.3² = 3⁴

9x - 2.9 = 81

9x - 18 = 81

9x = 81 + 18

9x = 99

x = 99 : 9

x = 11

h) 10x - 2².5 = 10²

10x - 4.5 = 100

10x - 20 = 100

10x = 100 + 20

10x = 120

x = 120 : 10

x = 12

i) 125 - 5.(4 + x) = 15

5.(4 + x) = 125 - 15

5.(4 + x) = 110

4 + x = 110 : 5

4 + x = 22

X = 22 - 4

x = 18

j) 2⁶ + (5 + x) = 3⁴

64 + 5 + x = 81

69 + x = 81

x = 81 - 69

x = 12

a) {-2).x = -10 => x = (-10): (- 2) => x = 5.

b)  (-18). x = -36 => x = (-36): (-18) => x = 2.

c) 2.x + 1 = 3=>2x = 2 => x = l.

d) (-4).x + 5 = -15 => (-4)x = (-15) -5 => (-4) x = -20 => x = 5.

a) {-2).x = -10 => x = (-10): (- 2) => x = 5.

b)  (-18). x = -36 => x = (-36): (-18) => x = 2.

c) 2.x + 1 = 3=>2x = 2 => x = l.

d) (-4).x + 5 = -15 => (-4)x = (-15) -5 => (-4) x = -20 => x = 5.

Help me

a)

\(x-5=-1\)

\(x=-1+5\)

\(x=4\)

b)

\(x+30=4\)

\(x=4-30\)

\(x=-26\)

c)

\(x-(-24)=3\)

\(x+24=3\)

\(x=3-24\)

\(x=-21\)

d)

\(22-(-x)=12\)

\(22+x=12\)

\(x=12-22\)

\(x=-10\)

e)

\(( x + 5 ) + ( x - 9 ) = x + 2\)

\(x+5+x-9=x+2\)

\(x+x-x=2+9-5\)

\(x=6\)

f)

\(( 27 - x ) + ( 15 + x ) = x - 24\)

\(27-x+15+x=x-24\)

\(-x+x-x=-24-15-27\)

\(-x=-66\)

\(x=66\)

x - 5 = -1                                         x  - (-24) = 3

x      = -1 + 5                                    x + 24 = 3

x     = 4                                             x         = 3 - 24

x + 30 =  4                                        x        = - 21

x         = 4 - 30                            22  - ( -x) = 12

x         = - 26                               22 + x     =  12

x + 5 + ( x - 9) = x + 2                         x     = 12 - 22          

x + 5 + x - 9    =  x + 2                         x    = -10

2x  - x             = 2 - 5 + 9              ( 27 - x) + ( 15 + x) = x - 24

x                     = - 3 + 9                    27 - x + 15 + x    = x - 24

x                     = 6                             27 + 15              = x - 24

                                                               x - 24 = 42  

                                                               x          = 42 + 24

                                                                x           = 66