123456789
-1•2+3+(4+5+6-7+8) +9 =
= 3-2 + ( 15-15) + 9 = 1 + 9 = 10
Надеюсь, что правильно поняла задание
1) 4× + 40 = 48
4× = 48 - 40
4× = 8
× = 2
4× - 48 + 40 = 0
4× = 48 - 40
4× = 8
× = 2
2) 3× + 2× - 7 = 13
5× = 13 + 7
5× = 20
× = 4
3× - 7 = 13 - 2×
3× + 2× = 13 + 7
5× = 20
× = 4
1) 17/300
3/25 = 36/300
2) 17/60
5/12 = 25/60
1/20 = 3/60
3) 19/180
11/30 = 66/180
1/15 = 12/180