X(1+y)/[x(1-y(]=(1+y)/(1-y)
y(1+x)/[y(1-x)]=(1+x)/(1-x)
1)а) 3х=15,6 х=5,2
б)8х+2=3х-18 5х=-20 х=-4
в)2х-(1+9х)=20 2х-1-9х=20 -7х=21 х=-3
2)4(у+2) (3у-1) при у=5
3)32 и 35 х+(х+3)=67 2х=64 х=32 х=32+3=35
4) х 2х х-500 1300 ,2600 ,2100
(5 - y)² - y(y - 3) = 25 - 10y + y² - y² + 3y = 25 - 7y