Question

5x+6y=-20, 9y+2x=25 решите систему уравнений(способ подстановки)

Answer 1

$\left \{ {{5x+6y=-20} \atop {9y+2x=25}} \right. \left \{ {{5x=-20-6y} \atop {9y+2x=25}} \right. \left \{ {{x= \frac{-20-6y}{5} } \atop {9y+2x=25}} \right. \left \{ {{x=-4-1,2y } \atop {9y+2(-4-1,2y)=25}} \right.$

$\left \{ {{x=-4-1,2y } \atop {9y-8-2,4y=25}} \right. \left \{ {{x=-4-1,2y } \atop {6,6y=33}} \right. \left \{ {{x=-4-1,2*5 } \atop {y=5}} \right. \left \{ {{x=-10 } \atop {y=5}} \right.$