Question

розвяжіть систему методом підстановки х+2у=7 5Х -у=2

Answer 1

$\left \{ {{x+2y=7} \atop {5x-y=2}} \right.\\\\\left \{ {{y=5x-2} \atop {x+2*(5x-2)=7}} \right.\\\\\left \{ {{y=5x-2} \atop {x+10x-4=7}} \right.\\\\\left \{ {{y=5x-2} \atop {11x=11}} \right.\\\\\left \{ {{x=1} \atop {y=5*1-2}} \right.\\\\ \left \{ {{x=1} \atop {y=3}} \right.\\\\Otvet:\boxed{(1;3)}$