1) X + (X+1) + (X+2) = 9; (Z-2) + (z-1) = - 3; 21 + (20-4x) - (11-1x) = 0.

2) 2u-3 (7-2u) = 3; 12-y=5 (4-2y) + 10; 2-2 (x-8) = 4x-4.

3) 3-5/7t=1-3/7t; 1/8u-2=5/8u+1; 2/5z-7=3.

1) 1.3x+3=9

3x=6

x=2

2. (z-2) + (z-1) = - 3

2z-3=-3

2z=0

z=0

3.21 + (20-4x) - (11-1x) = 0

21+20-4 х-11+1 х=0

30-3 х=0

-3 х=-30

х=10

2) 1.2u-21+6u=3

3u=24

u=8

2. 12-y=20-10y+10

-y+10y=-12+20+10

9y=18

y=2

3.2-2x+16=4x-4

-2x-4x=-2-16-4

-6x=-22

x=22/6=11/3

3) 1. 3-5/7t=1-3/7t

3-5/7t-1+3/7t=0

2/7t=0

t=o

2. 1/8u-2=5/8u+1

1/8u-2-5/8u-1=o

-3+4/8u=o

4/8u=3

u=24/4=6

3. 2/5z=3

z=3/2/5=15/2=7,5