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
2×(11х-5)-17х=55.
22х-10-17х=55.
5х-10=55.
5х=55+10.
5х=65.
х=65÷5.
х=13;
5×(8х+3)-12=83.
40х+15-12=83.
40х+3=83.
40х=83-3.
40х=80.
х=80÷40.
х=2;
7×(2х+9)+3х=114.
14х+63+3х=114.
17х+63=114.
17х=114-63.
17х=51.
х=51÷17.
х=3;
3×(4х+13)-25=74.
12х+39-25=74.
12х+14=74.
12х=74-14.
12х=60.
х=60÷12.
х=5.
621-307\2=157
156-66*9=810
20*3+30=90
801\3-100=87