Question

реши систему уравнений 5х+6y=-20
9y+2x=25

Answer 1

$left { {{5x+6y=-20 |-2} atop {9y+2x=25|5}} right.$

$left { {{-10x-12y=40} atop {45y+10x=125}} right.$

$left { {{-10x-12y=40} atop {33y=165}} right.$


$left { {{-10x-12*5=40} atop {y=5}} right.$

$left { {{-10x=100} atop {y=5}} right.$

$left { {{x=-10} atop {y=5}} right.$