Question

{х÷у×(х+у)=-4, х÷у+(х+у)=-3

Answer 1

Замена переменной 
х÷у=u;  x+y=v
Решаем систему
$left { {{uv}=-4 atop {u+v=-3}} right. \ \ left { {{ucdot(-3-u)}=-4 atop {v=-3-u}} right. \ \ left { {{u^2+3u-4=0 atop {v=-3-u}} right. \ \ left { {{u_1=-4; u_2=1 atop {v_1=1;v_2=-4}} right.$
1)$left { {{ frac{x}{y} =-4} atop {x+y=1}} right. \ \ left { {{x=-4y} atop {-4y+y=1}} right. \ \ left { {{y=- frac{1}{3} } atop {x= frac{4}{3} }} right.$

2)$left { {{ frac{x}{y} =1} atop {x+y=-4}} right. \ \ left { {{x=y} atop {2x=-4}} right. \ \ left { {{y=-2} atop {x=-2}} right.$