1) {2(х-2у)=х-8у
{5(х+у)=2(х-у)+10
2) {3(х+4у)-4х=2(2х+у)
{7 (х-5у)+6х=3(х+4у)+27
3) {15+2(х+3у)=3 (4х+у)
{2(5х-у)-3у=2+3 (2х-у)
4) {5 (7х+2у)-11у=6 (2х+у)+2
{33+3(6х-5у)=3 (х+2у)-5у