1) х:5=7:1/2
x*1/2=5*7
x*1/2=35
x=35:1/2
x=70
2) x:6=1/3:8
x*8=6*1/3
x*8=2
x=2:8
x=0.25
3) 60/x=5/7
x*5=60*7
x*5=420
x=420/5
x=84
4) x:2.43=2:5
x*5=2.43*2
x*5=4.86
x=4.86/5
x=0.972
5) x-5/20=6/7
x-5*7=20*6
x-5*7=120
x-5=120/7
x-5=17 1/7
x=17 1/7+5
x=22 1/7
6) 11/7=22/68x
11*68x=7*22
11*68x=154
68x=154/11
68x=14
x=14/68
x=7/34
7/28 = 1/4 - сократили на 7
11/44 = 1/4 - сократили на 11
Ответ: 7/28 и 11/44.
3.17+5.40=8.57. 16.27-8.57=7.7
Б) ( 2а + 3б ) ^2 = 4а^2 + 12аб + 9б^2 ;
B) ( 5x - 7 )^2 = 25х^2 - 70x + 49 ;
Г) ( 4a - б )^2 = 16a^2 - 8aб + б^2