\(a,565-\left(6x+70\right)=435\)

                       \(6x+70=565-435\)

                       \(6x+70=130\)

                                  \(6x=130-70\)

                                  \(6x=60\)

                                    \(x=10\)

\(b,100-7\left(x-5\right)=58\)

       \(100-7x+35=58\)

                  \(100-7x=58-35\)

                  \(100-7x=23\)

                                \(7x=100-23\)

                                \(7x=77\)

                                   \(x=11\)

a, 565-(6x+70)=435

6x+70=565-435

6x+70=130

6x=130-70

6x=60

x=60:6

x=6

b, 100-7(x-5)=58

7(x-5)=100-58

7(x-5)=42

x-5=42:7

x-5=6

x=6+5

x=11

a.  x = 8

a. 348 : x = 12 

x = 348 : 12

x = 29

b. 9x - 7 = 119 

9x = 119 + 7 

9x = 126 

x = 126 : 9 

x = 14 

c. 100 - 7 . ( x - 5 ) = 58 

7 . ( x - 5 ) = 100 - 58 

7 . ( x - 5 ) = 42 

x - 5 = 42 : 7

x - 5 = 6

x = 6 + 5

x = 11

d. x không thuộc số tự nhiên

a)348:x=12

x=348:12

x=29

b)9x-7=119

9x=119+7

9x=126

x=126:9

x=14

c)100-7.(x-5)=58

7.(x-5)=100-58

7.(x-5)=42

x-5=42:7

x-5=6

x=6+5

x=11

d)2^x-2.2³=64

2^x-2.8=64

2^x-16=64

2^x=64+16

2^x=80

đề sai

a ) 100-7(x-5)=58

=> 7(x-5)=42

=.> x-5 = 6

=> x=11

180-5(x+1)=30

=> 5(x+1)=150

=> x+1=30\

=> x=29

6x-5=613

=> 6x=618

=> x=103

a) \(100-7\left(x-5\right)=58\)

\(\Leftrightarrow7\left(x-5\right)=42\)

\(\Leftrightarrow x-5=6\)

\(\Leftrightarrow x=11\)

b) \(180-5\left(x+1\right)=30\)

\(\Leftrightarrow5\left(x+1\right)=150\)

\(\Leftrightarrow x+1=30\)

\(\Leftrightarrow x=29\)

c) \(6x-5=613\)

\(\Leftrightarrow6x=618\)

\(\Leftrightarrow x=103\)

1) (x - 35) - 120 = 0

x - 35 = 120

x = 120 + 35

x = 155

2) 310 - (118 - x) = 217

118 - x = 310 - 217

118 - x = 93

x = 118 - 93

x = 25

3) 156 - (x + 61) = 82

x + 61 = 156 - 82

x + 61 = 74

x = 74 - 61

x = 13

4) 814 - (x - 305) = 712

x - 305 = 814 - 712

x - 305 = 102

x = 102 + 305 = 407

5) 100 - 7 - (x - 5) = 58

x - 5 = 93 - 58

x - 5 = 35

x = 35 + 5 = 40

6) 12(x - 1) : 3 = 4³ + 2³

4(x - 1) = 72

x - 1 = 18

x = 18 + 1 = 19

7) 24 + 5x = 7⁵ : 7³

24 + 5x = 49

5x = 25

x = 25 : 5 = 5

8) 5(x - 1) : 3 = 4³ + 2³

\(\dfrac{5}{3}\left(x-1\right)=72\)

x - 1 = \(\dfrac{216}{5}\)

x = 221/5

9) 5(x - 4)² - 7 = 13

5(x - 4)² = 20

(x - 4)² = 4

\(\Rightarrow\left[{}\begin{matrix}x-4=2\\x-4=-2\end{matrix}\right.\)   \(\Rightarrow\left[{}\begin{matrix}x=6\\x=2\end{matrix}\right.\)

10) (x + 1) + (x + 2) + ... + (x + 30) = 795

=> (x + x + x + ... + x) + (1 + 2 + 3 +...+ 30) = 795 (1)

Đặt A = 1 + 2 + 3 +...+ 30

Số số hạng trong A là: (30 - 1) : 1 + 1 = 30 (số)

Tổng A bằng : (30 + 1).30 : 2 =465

Thay A = 465 vào (1) , ta được:

30x + 465 = 795

=> 30x =330

=> x =11

1: =>x-35=120

=>x=120+35=155

2: =>118-x=310-217=93

=>x=118-93=25

3: =>x+61=156-82=74

=>x=74-61=13

4: =>x-305=814-712=102

=>x=102+305=407

5: =>93-(x-5)=58

=>x-5=35

=>x=40

6: =>4(x-1)=64+8=72

=>x-1=18

=>x=19

7: =>5x+24=49

=>5x=25

=>x=5

8: =>5(x-1):3=4^3+2^3=64+8=72

=>5(x-1)=216

=>x-1=216/5

=>x=221/5

a: Ta có: \(100-7\left(x-5\right)=58\)

\(\Leftrightarrow7\left(x-5\right)=42\)

\(\Leftrightarrow x-5=6\)

hay x=11

b: Ta có: \(12\left(x-1\right):3=4^3+2^3\)

\(\Leftrightarrow12\left(x-1\right)=216\)

\(\Leftrightarrow x-1=18\)

hay x=19