Bài 1: Tìm x , biết:

1) x - 2 = -6 12) 3 . | x - 1 | - 5 = 7

2) -5 . x - ( -3 ) = 13 13) -12 . ( x - 5 ) + 7 . ( 3 - x ) = 5

3) 15 - ( x - 7 ) = -21 14) ( x - 2 ) . ( x + 4 ) = 0

4) 3 .x + 17 = 2 15) ( x - 2 ) . ( x + 15 ) = 0

5) 45 - ( x - 9 ) = -35 16) ( 7 - x ) . ( x + 19 ) = 0

6) ( -5 ) + x = 15 17) -5 < x < 1

7) 2 . x - ( -17 ) = 15 18) | x | < 3

8) | x - 2 | = 3 19) ( x - 3 ) . ( x - 5 ) < 0

9) | x - 3 | - 7 = 13 20) 2 . x² - 3 = 29

10) 72 - 3 . | x + 1 | = 9 21) -6 . x - ( -7) = 25

11) 17 - ( 43 - | x | ) = 45 22) 46 =- ( x - 11 ) = -48

Bài 7. Tìm x, y thuộc Z biết :

1/ x.(x + 7) = 0

2/ (x + 12).(x-3) = 0

3/ (-x + 5).(3 – x ) = 0

4/ x.(2 + x).( 7 – x) = 0

5/ (x - 1).(x +2).(-x -3) = 0

6/ ( x - 3). ( 2y + 1 ) = 7 ;

7/ ( 2x + 1).( 3y – 2) = -55.

Bài 8. Tìm x, y, z

Z biết : x – y = -9; y – z = -10; z + x = 11.

Bài 9. Tìm số nguyên a, b, c,d biết rằng:

a) a + b = - 11

b + c = 3

c + a = - 2

b) a + b + c + d = 1

a + c + d = 2

a + b + d = 3

a + b + c = 4

Bài 10-a: Cho x 1 + x 2 + x 3 + x 4 + ................ + x 49 + x 50 + x 51 = 0

và x 1 + x 2 = x 3 + x 4 = x 5 + x 6 = ..... = x 47 + x 48 = x 49 + x 50 = x 50 + x 51 = 1. Tính x 50?

Bài 10-b :

a) xy – 3x = -19 ;

b) 3x + 4y – xy = 16.

c) (x - 3). (y + 5) = -17

d) (x + 1). (xy – 2) = 11

e) xy - 7x + y = -22

f) xy - 3x + y = -20

g) xy - 5y - 2x= -41

Bài 1: Tìm x,biết

1) 2x - 5/7 = -19/7

2)   2(x - 5/7) = -19/7

3)  2/3 + 3/4 : x = -1/6

4) 5/2 - 3/4x  = 4/5

5) (4/5x - 50 ) : 2/3 = 21

6) (1/3 + 1/5 )x + 4/5 = 4 : 1/4

7) 3/5x - 1/2 = 3/7

8) 20 % x + 3/5 = 15

9) x : 5/4 = ( - 2 ) mũ 3

10) x. 2/5 = ( -1/5) mũ 2

11) x + 1/5 = 3/7 . - 4 /9

12) x: 3/25 = 12/-17 - 8/16

13) ( x - 4/7 ) : 2/5 = -5/7

14) ( 11/ + x ) . 50/23 = 15/23

15) 4. ( x - 6/7 ) - 3/5 = 1,4

16)  |3/4 x - 1/2 | - 1 = 1/4

Bài 1:

1)-7/9x2 3/4

2)2/3+1/3x-2/5

3) 3/4 x 15 1/3 - 3/4 x 43 1/3

4) (-49,1)x 13/27 - 58,9 x 13/27

5) 0,375 : (-4,5)

6) 3 1/7 :( -1 3/7)

7) 9 1/3 :4 2/3 - 2

8) ( 7 3/4 : 0,3125 + 4,5 x2 2/45) : (-8,5)

Bài 2 

A= (-6/11) x 7/10 x (11/-6) x(-20)

B= (-1/9) x (-17/29) x 58/51

C=(-3/7) x 5/11 +(-5/14)x5/11

D=(1 1/27 x 12/23 x 9/14 ) :(-3/23)

Bài 3 tìm x

a) 3/7x -2/5 x+-17/33

b)(3/4 x - 9/16).(1/3 +-3/5 : x)=0

c)(x+3/5 ) . (x+1)<0

(Hạn thứ 3 nha , giúp mk vs)