Решите систему уравнений: {х^2+ху=36 {ху+у^2=45 там общая фигурная скобка...

x(x+y)=36⇒x+y=36/xy(x+y)=45⇒x+y=45/y36/x=45/y⇒x=0,8y0,64y²+0,8y²=361,44y²=36y²=36:1,44=25y1=-5⇒x1=-5*0,8=-4y2=5⇒x2=4(-4;-5) (4;5)

 Сложим два уравнения [latex]x^2+2xy+y^2=36+45\ (x+y)^2=81\ x+y=+-9\\ x=9-y\ x=-9-y\\ (9-y)^2+y(9-y)=36\ (9-y)9=36\ 9-y=4\ y=5\ x=4\\ (-9-y)^2+y(-9-y)=36\ (-9-y)-9=36\ -9-y=-4\ y=-5\ x=-4[/latex]