1)(2/7х)(-1/3)(-21)=-5
-2/21х*(-21)=-5
2х=-5
х=-5:2
х=-2,5
2)х+(16/25-4/5)=-17/5:5/6
х-4/25=-17/5*6/5
х-4/25=-102/25
х=-102/25+4/25
х=-98/25
х=-3,92
3)-3/7у=-6/7*2,5
-3/7у=-15/7
у=15/7*7/3
у=15:3
у=5
4)х-(1 5/7-1/3)=-1 2/5:0,5
х-(12/7-1/3)=-7/5*2
х-29/21=-14/5
х=-14/5+29/21
х=(-294+145)/105
х=-149/105
х=-1 целых 44/105
5)-3/7*2 4/5х*(-0,6)=-1,44
-3/7*14/5х*(-3/5)=-1,44
-6/5х*(-3/5)=-1,44
18/25х=-144/100
х=-144/100*25/18
х=-8/4
х=-2
7)0,24х*(-1/3)=0,08
-0,08х=0,08
х=0,08:(-0,08)
х=-1
8)-12у*0,06=1,44
-0,72у=1,44
у=1,44:(-0,72)
у=-2