Пошаговое объяснение:
1) = 0
2) = 21c
3) = 9a + 6b
4) = -11c - 7a
5) = 1,2y
1) = 3b + 5a - 7b = 5a - 4b
2) = -3x - 8y + 3x = -8y
3) = -11a - b - 12a + 3b = -23a + 2b
4) = 24a - 12 + 6a = 30a - 12
5) = 7p - 6p + 2 = p + 2
6) = -12a - 8 + 8 = -12a
