Question

Решите системное линейное уравнение способом подcтановки 5x-y=4 9x-2y=5

Answer 1

$\left \{ {{5x-y=4} \atop {9x-2y=5}} \right. \\\\\left \{ {{y=5x-4} \atop {9x-2(5x-4)=5}} \right.\\\\\left \{ {{y=5x-4} \atop {9x-10x+8=5}} \right.\\\\\left \{ {{y=5x-4} \atop {-x=5-8}} \right.\\\\/left \{ {{x=3} \atop {y=5*3-4}} \right.\\\\\left \{ {{x=3} \atop {y=11}} \right.$

Ответ : (3 ; 11)