1.{3х-у=7. |*3
{2х+3у=1
{9х-3у=7
{2х+3у=1
_______
11х=8
х=8/11
2/1*8/11+3у=1
16/11+3у=1
3у= 11/11-16/11
3у=-5/11
у= - 5/11*1/3
у= - 5/33
От: ( 8/11; - 5/33)
2)
{4х+у=5 |*2
{-х-2у=11
{8х+2у=10
{-х-2у=11
________
7х=21
х=3
-3-2у=11
-2у= 14
у= - 7
От: (3; -7)