А) *=6, *=7, *=8,*= 9
Б) *= 9
(140 - 80) : 4 * 5 = 75 8 * 30 - 30 : (3 * 5) = 240 - 30 : 15 = 238
(140 - 80 : 4) * 5 = 600 8 * (30 - 30) : 3 * 5 = 0
140 - 80 : (4 * 5) = 136 (8*30 - 30) : 3 * 5 = 210:3*5=70*5= 350
6 - 4х = 4 - 6(х - 7)
6 - 4х = 4 - 6х - 6 *(-7)
6 - 4х = 4 - 6х + 42
6 - 4х = - 6х + 46
-4х + 6х = 46 - 6
2х = 40
х = 40 : 2
х = 20
------------------------------------
6 - 4*20 = 4 - 6(20-7)
6 - 80 = 4 - 6 * 13
- 74 = 4 - 78
- 74 = - 74