x=20+y;
1/(20+y)-1/y=4/15.
<=>
(y-20-y)/(20y+y^2)=4/15.
***
-20/y^2+20y=4/15
4y^2+80y=-300
y^2+20y+75=0
D=400-300=100
y1=-5
y2=-15
x1=15
x2=5
ответ: (5:-15); (15;-5)
x=20+y;
1/(20+y)-1/y=4/15.
<=>
x=20+y;
(y-20-y)/(20y+y^2)=4/15.
***
-20/y^2+20y=4/15
4y^2+80y=-300
y^2+20y+75=0
D=400-300=100
y1=-5
y2=-15
x1=15
x2=5
ответ: (5:-15); (15;-5)