Пошаговое объяснение:
18/1*2/21=6/1*2/7=12/7
12/1*3/24=1/1*3/2=3/2
8/1*1/16=1/2
9/1*1/27=1/3
9/1*9/1=81
12/25*1/5=12/125
21/3*1/17=21/51
25/36*1/2=5/6*1/2=5/12
2.
1. =28,46
2.-71,39
3.3,49
4.-18,3
3.-4х-8х=16,-12х=16, - х=4/3, х=-4/3
-7х=14, - х=2, х=-2
4.
39,45
29,12
0,16
-2,8
-1,5
