Question

реши систему уравнений {2x+y=0 3x-2y=-7

Answer 1

y = -2x Подставляем в 3x-2y= -7: 7x=7 => x=1 y = -2

Answer 2

$\left \{ {{y=-2x} \atop {3x-2*-2x=-7}} \right. = \left \{ {{y=-2x} \atop {3x+4x=-7}} \right.= \left \{ {{y=-2x} \atop {7x=-7}} \right.= \left \{ {{y=-2x} \atop {x=-1}} \right. \left \{ {{y=2} \atop {x=-1}} \right.$