Question

Решите систему уравнения методрм подстановки{ х-у=1
{х+2у=3

Answer 1

$left { {{x-y=1} atop {x+2y=3}} right. \ \ left { {{x=1+y} atop {x+2y=3}} right. \ \ 1+y+2y=3 \ 3y=3-1 \ 3y=2 \ y= frac{2}{3} \ \ x=1+ frac{2}{3}=1 frac{2}{3}= frac{5}{3}$