Система:

25x+2y=-40
2x-y=1

25х+2у=40 --- 25х+2у=40
-у=1-2х (-1)--- у=2х-1
25х+2(2х-1)=40
25х+4х-2=40
29х=42
х=42/29
х= 1 целая 13/29