6) - 5 (3 а+1) + 11=-16-2 (3-а)

9) 0,9 * (4y-2) = 0,5 (3y-4) + 4,4

10) 8,5x-2,15x=3,05x-9,5

12) - 3 (2,1x-4) - 4,2=1,2 (-5x+0,5)

6) - 18a - 5 + 11 = - 16 - 6 - a

-18a + 12 = - 22 - a

-17a = - 34

a = - 34 / - 17

a = 2

9) 3.2y - 1.8 = 1.5y - 2 + 4.4

3.2y - 1.5y = - 2 + 1.8 + 4.4

2.7y = 4.2

y = 1. (5)

10) 8.5x - 2.15x - 3.05x = - 9.5

3.3x = - 9.5

x = 2.87

12) - 6.3x + 12 - 4.2 = - 6x + 0.6

-6.3x + 6x = - 12 + 4.2 + 0.6

-0.3x = - 7.2

x = 24