х=(21-11y)/5
8(21-11y)/5-23y+7=0
(8(21-11y)-115y+35)/5=0
8(21-11y)-115y+35=0
168-88y-115y+35=0
203-203y=0
y=1
x=(21-11)/5=2
x=2
х=(21-11y)/5
8(21-11y)/5-23y+7=0
(8(21-11y)-115y+35)/5=0
8(21-11y)-115y+35=0
168-88y-115y+35=0
203-203y=0
y=1
x=(21-11)/5=2
x=2
y=1