Решить систему {ху -2(х+у)=2                         
                          { ху+х+у=29

x+y=29-xy
xy-2*(29-xy)=2
xy-58+2xy=2
3xy=60
xy=30
x+y+30=29
x+y=-1
x=-1-y
-(1+y)*y-2(-1-y+y)=2
-(y+y^2)-2(-1)=2
-(y+y^2)+2=2
-y^2-y=0
y(-y-1)=0
-y(y+1)=0
y1=0   y2=-1
x1=-1-0=-1    x2=-1-(-1)=-1+1=0