{10(x+4)(y+1)=30(x-1)(y-1)
{30(x-1)(y-1)=20xy
10(x+4)(y+1)=20xy
(x+4)(y+1)=2xy
xy+x+4y+4=2xy
xy-x=4y+4
x(y-1)=(4y+4)
x=(4y+4)/(y-1)
10[(4y+4)/(y-1)+4](y+1)=30[(4y+4)/(y-1) -1](y-1)
[(4y+4)/(y-1)+4](y+1)=3[(4y+4)/(y-1) -1](y-1)
(4y+4+4y-4)(y+1)/(y-1)=3(4y+4-y+1)(y-1)/(y-1)
8y(y+1)=(9y+15)(y-1),y≠1
8y²+8y=9y²-9y+15y-15
y²-2y-15=0
y1+y2=2 U y1*y2=-15
y1=-3⇒x1=(-12+4)/(-3-1)=-8/(-4)=2
y2=5⇒x2=(20+4)/(5-1)=24/4=6
Ответ (2;-3);(6;5)