2) x+5.7 / 2.5 = 2x - 1 / 4
(x+5.7)*8 - (2x-1)*5 (дробь) / 20 = 8x+45,6-10x+5 / 20 = 0
-2x+50.6 = 0
2x=50.6
x=25.3
1) (5 3/20 - 4.2) + (3.11 + 1 2/5) = (103/20-42/10)+(311/100+7/5) = 103-84 / 20 + 311 + 140 / 100 = 19/20+451/100 = 95+451 / 100 = 546 / 100 = 5.46