(5/7)^(-2)=(7/5)^2=49/25=1 24/25=1.96
(1.4)^(-2)=(14/10)^(-2)=(10/14)^(2)=100/196
1.4
b) (1.4)^(-2), 1.4, (5/7)^(-2)
Тут два варианта 7•8=56
64-56=8
1,845÷2,3+4,5•(8,6•0,25-(2 61/90 -1 1/12)) •(0,6+1,34) = 369/200÷23/10+9/2•(2,15-(241/90-13/12)) •1,94 = 369/200•10/23+9/2•(43/20-287/180)•97/50 = 369/20•1/23+9/2•5/9•97/50 = 369/460+1/2•97/10 = 369/460+97/20 = 5 15/23