Question

{x-y=20 1x-1y=415 решитееееееее*

Answer 1

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)