6. Спрости вираз: 1) -4,5m * (-2n); 2) -3a + 2b + 5a - 8b.

1) $$-4,5m \cdot (-2n) = -4,5 \cdot (-2) \cdot m \cdot n = 9mn$$ 2) $$-3a + 2b + 5a - 8b = (-3a + 5a) + (2b - 8b) = (5 - 3)a + (2 - 8)b = 2a - 6b$$