a)2(x - 2) + 7.(3 - x) = -2.(3x - 18)

=> 2x - 4 + 21 - 7x = -6x - 36

=> 2x - 7x + 6x = 36 - 21 + 4

=> x = 19

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) \(\left(x-1\right)^3=8=2^3\)

\(x-1=2\)

\(x=2+1=3\)

b) \(7^{2x-6}=49=7^2\)

\(2x-6=2\)

\(2x=6+2=8\)

\(x=8:2=4\)

c) \(\left(2x-14\right)^7=128=2^7\)

\(2x-14=2\)

\(2x=14+2=16\)

\(x=16:2=8\)

d) \(x^4\cdot x^5=5^3\cdot5^6=5^4\cdot5^5\)

\(x=5\)

e) \(3\cdot\left(x+2\right):7\cdot4=120\)

\(x+2=120:3\cdot7:4\)

\(x+2=70\)

\(x=70-2=68\)

Lời giải:

a. $(x-1)^3=8=2^3$
$\Rightarrow x-1=2$

$\Rightarrow x=3$

b. $7^{2x-6}=49=7^2$
$\Rightarrow 2x-6=2$

$\Rightarrow 2x=8$

$\Rightarrow x=4$

c. $(2x-14)^7=128=2^7$

$\Rightarrow 2x-14=2$

$\Rightarrow 2x=16$

$\Rightarrow x=18$

d.

$x^4.x^5=5^3.5^6$

$x^9=5^9$

$\Rightarrow x=5$

e. 

$3(x+2):7=120:4=30$

$3(x+2)=30.7=210$

$x+2=210:3=70$

$x=70-2=68$

a,1/4

b,8

a, 1/4
b,8

a) x=1/4

b) -12

c) 50

d)Vậy x e thuộc {-3, -2, -1}

\(\left[8x-120:4\right]\times3^3=3^6.\)

\(8x-120:4=3^3\)

\(8x-30=27\)

\(8x=27+30\)

\(8x=57\)

\(x=19\)

123 - 5.(x + 4) = 38

123 - 5x - 20 = 38

-5x = 38 - 123 + 20

-5x = -65

x = -65 : -5

x = 13

Vậy x = 13

\(123-5\left(x+4\right)=38\)

\(5\left(x+4\right)=123-38\)

\(5\left(x+4\right)=85\)

\(\left(x+4\right)=17\)

\(x=17-4\)

\(x=13\)

\(\left(3x-2^4\right)\times7^3=2\times7^4\)

\(\left(3x-2^4\right)=2\times7^4:7^3\)

\(\left(3x-2^4\right)=2\times7\)

\(3x-2^4=14\)

\(3x-16=14\)

\(3x=30\)

\(x=30:3\)

\(x=10\)

e: =>x=0 hoặc x=1

a:565-13.x=30

13.x=565-370

13.x=195

x=195:13

x=15

Nếu sai sót gì thì e xin lỗi ạ ^^

a,x-6/7=5/2

x=5/2+6/7

x=47/14

b,12/7:x+2/3=7/5

12/7:x=7/5-2/3

12/7:x=11/15

        x=12/7:11/15

x=180/77

c,2/3.x+3/4=3

2/3.x=3-3/4

2/3.x=9/4

     x=9/4:2/3

    x=27/8

d,720:[41-(2x-5)]=120

         [41-(2x-5)]=720:120

        [41-(2x-5)]=6

              (2x-5)=41-6

               (2x-5)=35

                2x=35+5

               2x=40

               x=40:2

               x=20

lấy máy tính ra mà tính

lấy máy tính ra bạn ơi

ai help vs  :(((

275-(113+x)+63=158
275-(113+x)=95
113+x=175-95
113+x=80
x=80-113
x=33

[3(x+2):7]4=120
3(x+2):7=30
3(x+2)=210
x+2=70
x=68

Cái đề thiếu rồi nha bạn

Phải bằng bao nhiêu chú

[3x(x+2):7]x4=?