12 – 2,5 (3х - 5) = 0.8 (5 – 10х)
12 - 7,5 x + 12.5 = 4 - 8x
-7.5x+8x = 4-12-12.5
0.5x = -20.5
x= -20.5: 0,5
x= -41
