1) (7x++3) = 5 2) (8x+11)-13=9x-5 3)2=(3x--4x) 4)8x+5 = 119+(7-3x) 5)6x+(3x-2) = 14 6) 8y-(7y-142) = 51 7) 11x+103=1+(12x-31)

7х + 1 - 6х - 3 = 5
х = 5 - 1 + 3
х = 7

8х + 11 - 13 = 9х - 5
8х - 9х = -11 + 13 - 5
-х = - 3
х = 3

3х - 5 - 7 + 4х = 2
7х = 2 + 5 + 7
7х = 14
х = 2

8х + 5 = 119 + 7 - 3х
8х + 3х = 119 + 7 - 5
11х = 121
х = 11

6х + 3х - 2 = 14
9х = 14 + 2
9х = 16
х = 1целая 7/9

8у - 7у + 142 = 51
у = -142 + 51
у = - 91

11х + 103 = 1 + 12х - 31
11х - 12х = - 103 + 1 - 31
- х = -133
  х = 133