Question

х+у=6 5х-2у=9 решите способом подстановки ​

Answer 1

Ответ:

$x=3; y=3$

Объяснение:

$\left \{ {{x+y=6} \atop {5x-2y=9}} \right. \\\\\\\left \{ {{-5x-5y=-30} \atop {5x-2y=9}} \right. +\\\\\\-7y=-21\\y=\frac{-21}{-7} \\y=3\\\\\\x+y=6\\x+3=6\\x=6-3\\x=3$