1/x-1/y=8
2/x-1/y=13
y-x=8xy
2y-x=13xy
y-x-8xy = 0
y-x(1+8y)=0
-x(1+8y)=-y
x=y/(1+8y)
2y(1+ 8y)-y =13 y^2/(1+8y)
(2y+16y^2-y) (1+8y)=13y^2
y=0
Там не видно что то
{x^2+y^2=68
{xy=16
x=16/y
256+y^4=68y^2
y^2=t
t^2-68t+256=0
D=3600
t =4
t2 = 64
y^2=4
y=2
y=8
Ответ ( 4 2) (64 8)