a: 12:x=144

=>\(x=\dfrac{12}{144}\)

=>\(x=\dfrac{1}{12}\)

b: \(x-17=\left(-2\right)\cdot27\)

=>\(x-17=-54\)

=>\(x=-54+17=-37\)

c: \(3x-125=145\)

=>\(3x=125+145=270\)

=>\(x=\dfrac{270}{3}=90\)

\(a,12:x=144\\ x=\dfrac{12}{144}=\dfrac{1}{12}\\ ---\\ b,x-17=\left(-2\right).27\\ x-17=-54\\ x=-54+17=-37\\ ----\\ 3x-125=145\\ 3x=145+125=270\\ x=\dfrac{270}{3}=90\)

a: 12:x=144

x=\(\dfrac{1}{12}\)

b: 

c: 

x=90

a: Ta có: \(7x+25=144\)

\(\Leftrightarrow7x=119\)

hay x=17

b: Ta có: \(33-12x=9\)

\(\Leftrightarrow12x=24\)

hay x=2

c: Ta có: \(128-3\left(x+4\right)=23\)

\(\Leftrightarrow3\left(x+4\right)=105\)

\(\Leftrightarrow x+4=35\)

hay x=31

d: Ta có: \(71+\left(726-3x\right)\cdot5=2246\)

\(\Leftrightarrow5\left(726-3x\right)=2175\)

\(\Leftrightarrow726-3x=435\)

\(\Leftrightarrow3x=291\)

hay x=97

e: Ta có: \(720:\left[41-\left(2x+5\right)\right]=40\)

\(\Leftrightarrow41-\left(2x+5\right)=18\)

\(\Leftrightarrow2x+5=23\)

\(\Leftrightarrow2x=18\)

hay x=9

Bn cần bài nào vậy

f: Ta có: \(10-4x+120:8=16+1\)

\(\Leftrightarrow4x=17-25=-8\)

hay x=-2

g: Ta có: \(x+9x+7x+5x=2244\)

\(\Leftrightarrow22x=2244\)

hay x=102

h: Ta có: \(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+100\right)=5750\)

\(\Leftrightarrow100x+5050=5750\)

\(\Leftrightarrow100x=700\)

hay x=7

570 :  x = 5

x = 570 : 5

x = 114

Bài 1:

a) −x + 8 = −17

−x = −17 − 8

−x = −25

⇒ x = 25

Vậy x = 25

x = −2

c) x − 45 = −17

x = −17 + 45

x = 28

Vậy x = 28

d) |x + 1| = 20 (>0)

TH₁: x + 1 = 20       TH₂: x + 1 = −20

x = 20 − 1                        x       = −20 − 1

x = 19                              x       = −21

Vậy x∈\(\left\{-21;19\right\}\)

e) |x − 3| − 16 = −4

|x − 3| = −4 + 16

|x − 3| = 12 (>0)

TH₁: x − 3 = 12             TH₂: x − 3 = −12

x = 12+3                                x = −12 + 3

x = 15                                    x = −9

Vậy x∈\(\left\{-9;15\right\}\)

b) 35 − x = 37

x = 35 − 37

x = −2

Vậy x = −2

Bài 2: 

a) (144 − 97) − 144

= 144 − 97 − 144
= (144 − 144) − 97
= − 97

b) (−145) − (18 − 145)

= −145 − 18 + 145

= (−145 + 145) − 18

= −18

c) (27 + 514) − (486 − 73)

= 27 + 514 − 486 + 73

= (27 + 73) + (514 − 486)

= 100 + 28

= 128

d) (38 − 29 + 43) − (43 + 38)

= 38 − 29 + 43 − 43 − 38

= (−38 + 38) + (−43 + 43) − 29

= 0 + 0 − 29

= −29

a. 231 - x = 105

           x = 231 – 105

           x = 126

b. x – 86 = 97

           x = 97 + 86

           x = 183

a) x + 216 = 570

x = 570 – 216

x = 354

b) x – 129 = 427

x = 427 + 129

x = 556

Câu 3:

a: (x-5):2=7

=>x-5=14

hay x=19

b: 86-(5x+3)=38

=>5x+3=48

=>5x=45

hay x=9

a)  x - 12 = 14 x = 14 + 12 x = 26

b)  2 x - 13 = 3 . 17 2 x = 51 + 13 2 x = 64 x = 64 : 2 x = 32

c)  x - 43 = 2 . 18 x = 36 + 43 x = 79

d)  x - 14 . 39 = 0 x - 14 = 0 x = 14

e)  13 - x . 28 = 28 13 - x = 28 : 28 13 - x = 1 x = 13 - 1 x = 12

f) 22 . 35 - x = 22 35 - x = 1 x = 35 - 1 x = 34

g)  x - 24 : 2 = 18 x - 12 = 18 x = 39

h) 400 + 275 - x = 570 275 - x = 570 - 400 275 - x = 170 x = 275 - 170 x = 105

a. = 285

b. = ?

A chị ghi ra rõ lun giùm e cái

a) làm sao

b) làm sao