-8 + 6.5 + 4 - 9 = - 17 + 10.5 = - 6.5
............................................
2)
A) - 0.3X = 9
X = - 30
B) 15X = 3X + 24
12X = 24
X = 2
C) 5Y = 15.5
Y = 3.1
................................
7X = Y
X + 75 = 0.5Y
..............
X + 75 = 3.5X
2.5X = 75
X = 30
Y = 210
ответ: 210 + 30 = 240 литров