4. Вычислите удобным способом:
1) – 84 * 15 + 84 * 14, 2) – 49 * 51 + 39 * 51,
3) – 148 + 139 –( - 11 – 148 )

1) (-84 • 15 + 84 • 14,2) - 49 • 51 + 39 • 51 = -4458.8

1. 0 + 15 + 14,2 = 29.2

2. 49 • 51 = 2499

3. 39 • 51 = 1989

4. 2499 + 1989 = 4488

5. 29.2 - 4488 = - 4458.8

2) -148 + 139 - (-11 - 148) = -168

1. -11 - 148 = -159

2. -148 + 139 = -9

3. -9 - 159 = -168