А) 3 (x + 2) - x = 10.
3x + 6 - x = 10.
2x = 4.
x = 2.
в)4x + 3(x - 7) = 5.
4x + 3x - 21 = 5.
7x = 26.
x = 26/7.
д) 5 - x = 4(x - 3).
5 - x = 4x - 12.
-x - 4x = - 12 - 5
-5x = -17.
x = 3,4.
ж) 7 - (2x + 3) = 9.
7 - 2x - 3 = 9.
-2x = 5.
x = - 2,5.
и)1/2 (x - 4) + 3x = 5.
(1/2)x - 2 + 3x = 5.
3,5x = 7.
x = 2.
л) 5x - ((1/2)x + 9) = 18.
5x - (1/2)x - 9 = 18.
4,5x = 27.
x = 6.