a)5x - 3 + 2x = 4x + 9
7x - 3 = 4x + 9
7x - 4x = 9 + 3
3x = 12 /:3
x = 4
b) 2,5 = 2x + 8,5
2,5 - 8,5 = 2x
- 6 = 2x /:2
-3 = x
c) 2 (2x - 4) = 2x + 8
4x - 8 = 2x + 8
2x = 16 /:2
x = 8
d) 12 (3y + 1) = 5 (8y+3)
36y + 12 = 40y + 15
-3 = 4y /:4
-3/4 = y
e) 8 (3x - 2) - 13x = 5 (12 - 3x) + 7x
24x - 16 - 13x = 60 - 15x + 7x
11x - 16 = 60 - 8x
19x = 76 /:19
x = 4
f) 7 (2x - 14) - 5 (x - 18) = -4 (3 - 2x)
14x - 98 - 5x + 90 = -12 + 8x
9x - 8 = - 12 + 8x
x = -4
