1. -16a - 14b + 4a - 8b = -12a - 22b
2. 10x - 15 - 6 + 4x = 15 - 6x - 6
10x + 4x + 6x = 15 - 6 + 6 + 15
20x = 30
x = 1.5
3. S = 3x
S = (x + 15)*2.4
3x = 36 + 2.4x
0.6x = 36
x = 60 км/ч - скорость автомобиля
S = 60 * 3 = 180 км
4. 2 2/5 - 3 4/7 = 12/5 - 25/7 = 84/35 - 125/35 = -41/35
5 6/7 * -35/41 = 41/35 * -35/41 = -1
1 7/12 - 1 = 7/12
5. а) 75 = 33.3% от 225
на 66.7% дороже
б) на 66.7% дешевле