Question

розв'язати систему

у-х=5
х+2у=4​

Answer 1

$\left \{ {{y-x=5} \atop {x+2y=4}} \right. =\left \{ {{-x+y=5} \atop {x+2y+4}} \right. \\\\x_{1} =-2=-2\\y_{1} =3=3\\\\y=3\\x=-2$