1){-4x+5y=20
{4X+3y=12
2){3Х+4y=24
{1,5x+y=-3
3){x+2y=-6
{x+2y=4

1)-4х+5у=204х+3у=12,5у=20+4ху=(20+4х):54х+3((20+4х):5)=124х+3(4+4х)=124х+12+12х=1216х=0х=0, у=42)3х+4у=241.5х+у=-3у=-3+1.5х3х+4(-3+1.5х)=243х-12+6х=249х=36х=4, у=-9