Question

$left { {{ frac{x+y}{x-y}= frac{3}{2} } atop {xy=80}} right.$

Answer 1

$displaystyle left { {{ frac{x+y}{x-y} = frac{3}{2} } atop {xy=80}} right. Rightarrow left { {{2x+2y=3x-3y} atop {xy=80}} right. Rightarrow left { {{x=5y} atop {5ycdot y=80}} right. \ 5y^2=80|:5\ y^2=16\ y=pm 4\ x=pm 20$


Ответ: $(-20;-4),,,,, (20;4).$