\(71+\left(26-3x\right)\div5=75\)

\(\left(26-3x\right)\div5=4\)

\(26-3x=20\)

\(3x=6\Leftrightarrow x=2\)

\(20-\left[7\left(x-3\right)+4\right]=2\)

\(7x-21+4=18\)

\(7x-17=18\)

\(7x=25\Leftrightarrow x=\frac{25}{7}\)

a)17-(12+13)

=17-25

=-8

b)2347-450-347-550

=(2347-347)-(450+550)

=2000-1000

=1000

c)(-71).(-175)-75.71

=71.(175-75)

=71.100

=7100

d)93.(27-100)+(-3)^3.93

=93.(27-100)+(-27).93

=93.((-27)+(-73))

=93.(-100)

=-9300

bài 2 :

a)x-15=-20

        x=-20+15

        x=-5 

b)3x+27=6

 3x=6-27

 3x=-21

    x=-21:3

    x=-7

c)3.(x-1)+27=102

  3.(x-1)=102-27

 3.(x-1)=75

   x-1=75:3

   x-1=25

     x=25+1

    x=26

d)|x-6|.7-(-2)^2=-8+39 

sory ,câu này mk ko làm đc  

a,  3(x+3)-2(x-5)=11

=> 3x+9-2x+10=11

=> 3x-2x=11-10-9

=>  x=-8

Vậy.........

b,   14-4|x|=-6

=>  -4|x|=8

=>   |x|=-2(VL vì trị tuyệt đối luôn lớn hơn hoặc = 0)

Vậy......

Câu a:

2.(x + 2/5) + 1 1 /4 = 11/20

2x + 4/5 + 5/4 = 11/20

2x = 11/20 - 5/4 - 4/5

2x = 11/20 - 25/20 - 16/20

2x = -30/20

2x = -3/2

x = -3/2 : 2

x = - 3/4

Vậy x = - 3/4

Câu b:

x - 1 1/8 - 2/3x - 5/6x = 75%

(x - 2/3x - 5/6x) = 75% + 1 1/8

x (1 - 2/3 - 5/6) = 3/4 + 9/8

x (6/6 - 4/6 - 5/6) = 6/8 + 9/8

x.(-1/2) = 15/8

x = 15/8 : (-1/2)

x = 15/8 x (-2)

= -15/4

a) \(2.\left(x+\frac{2}{5}\right)+1\frac{1}{4}=\frac{11}{20}\)

\(2.\left(x+\frac{2}{5}\right)+\frac{5}{4}=\frac{11}{20}\)

\(2.\left(x+\frac{2}{5}\right)=\frac{-7}{10}\)

\(x+\frac{2}{5}=\frac{-7}{20}\)

\(x=\frac{-13}{20}\)

Vậy \(x=\frac{-13}{20}\)

b)\(x-1\frac{1}{8}-\frac{2}{3}x-\frac{5}{6}x=75\%\)

  \(\left(x-\frac{2}{3}x-\frac{5}{6}x\right)-\frac{9}{8}=\frac{3}{4}\)

\(\frac{-1}{2}x-\frac{9}{8}=\frac{3}{4}\)

\(\frac{-1}{2}x=\frac{15}{8}\)

\(x=\frac{-15}{4}\)

Vậy \(x=\frac{-15}{4}\)

a)(9x+2)x3=60

        9x+2 =60:3

        9x+2  =20

              9x =20-2

              9x=18

                x=18:9

                 x=2

a,x=2

b,x=2

c,x=9

(20-3.x):5=55-51

(20-3.x):5=4

20-3.x=4.5

20-3.x=20

3.x=20-20

3.x=0

x=0:3

x=0

không đc đừng ném mik nha

Câu b:

71 + (26 - 3\(x\)) : 5 = 75

(26 - 3\(x\)) : 5 = 75 - 71

(26 - 3\(x\)) : 5 = 4

(26 - 3\(x\)) = 4 x 5

26 - 3\(x\) = 20

3\(x\) = 26 - 20

3\(x\) = 6

\(x=6:3\)

\(x\) = 2

Vậy \(x=2\)

a,17-3x-11=31-2x

=>  6 - 3x = 31 - 2x 

=> 6 - 31 = - 2x + 3x

=> x = - 25

Vậy x = - 25

b,12 - | x + 3 |=5

=> | x + 3 | = 7 

\(\Rightarrow\orbr{\begin{cases}x+3=7\\x+3=-7\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=4\\x=-10\end{cases}}\)

Vậy \(x\in\left\{4;-10\right\}\)

c,4 x+ (-46) = -30

=> 4x =  - 30 + 46 

=> 4x = 16

=> x = 4

Vậy x = 4

d,   -20 + (5x - 5 ) = 60

= > - 20 + 5x - 5 = 60

=> 5x = 60 + 20 + 5

=> 5x = 85

=> x = 17

Vậy x = 17

e,   10 + |1 - 2x |= 15

=> | 1 - 2x | = 5

\(\Rightarrow\orbr{\begin{cases}1-2x=5\\1-2x=-5\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}2x=-4\\2x=6\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=-2\\x=3\end{cases}}\)

Vậy \(x\in\left\{-2;3\right\}\)

Dài qua lần sau đừng đăng nhiều như v

Tự nghĩ k đc à

@@ Học tốt @@

## Chiyuki Fujito