Х+у =3-х+у 4 2 3х+2у - х+3у =5 3 7 решите уравнение подстановки

х+у=3-х+у

423х+2у-х+3у=537

423x+2y-x+3y=537

y=-84.4x+107.4

х+у=3-х+у
x+(-84.4x+107.4)=3-x+(-84.4x+107.4)

-82.4x+104.4+84.4x-107.4=0

2x-3=0

x=3/2
x=1.5

423x+2y-x+3y=537
423*(1.5)+2y-1.5+3y=537

96+5y=0

y=-96/5

y=-19.2