Ответ:
1)3/4 • 4=3/1=3
2)3-3/4=2 1/4
Пошаговое объяснение:
87-(41+у)=22
41+у=87-22
41+у=65
у=65-41
у=24
-------------------
87-(41+24)=22
22=22
a/48=7/12,
12a = 48*7
12a = 336
a = 336 : 12
a = 28
25/4=b/12,
4b = 25 * 12
4b = 300
b = 300 : 4
b = 75
9/c=3/17,
3c = 17*9
3c = 153
c = 153 : 3
c = 51
12/x=2/15
2x = 15*12
2x = 180
x = 180 : 2
x = 90