9-(8х-11)=12 11х+103=1+(12х-31) (2х+3)+(3х+4)+(5х+5)=12-7х 6х=1-(4-6х)

1) —9 — (8x — 11) = 12
—9 — 8x + 11 = 12
—8x = 12 — 11 + 9
—8x = 10
x =  =  = —1,25;

2) 11x + 103 = 1 + (12x — 31)
11x + 103 = 1 + 12x — 31
11x — 12x = 1 — 31 — 103
—x = —30 — 103
—x = —133
x = 133; 

3) (2x + 3) + (3x + 4) + (5x + 5) = 12 — 7x
2x + 3 + 3x + 4 + 5x + 5 = 12 — 7x
(2x + 3x + 5x) + (3 + 4 + 5) = 12 — 7x
10x + 12 = 12 — 7x
10x + 7x = 12 — 12
17x = 0
x =  = 0; 

4) 6x = 1 — (4 — 6x)
6x = 1 — 4 + 6x
6x — 6x = 1 — 4
0x = —3
Уравнение не имеет решений.