х+3у=9
3х-у=7
x=9-3y
3(9-3y)-y=7
27-9y-y=7
-10y=7-27=-20
y=20/10=2
x=9-3*2=9-6=3
ответ: (3; 2)
3х-у=7 /*3
x+3y=9
9x-3y=21
10x=30
x=3
y=(9-x)/3 = (9-3)/3 = 6/3 = 2
(3; 2)
х+3у=9
3х-у=7
x=9-3y
3(9-3y)-y=7
27-9y-y=7
-10y=7-27=-20
y=20/10=2
x=9-3*2=9-6=3
ответ: (3; 2)
х+3у=9
3х-у=7 /*3
x+3y=9
9x-3y=21
10x=30
x=3
y=(9-x)/3 = (9-3)/3 = 6/3 = 2
(3; 2)