Question

Помогите по-братски​

Answer 1

$\frac{x^{2}+y(3x+11y) }{xy+2y^{2}} =5\\\\\frac{x^{2}+3xy+11y^{2}}{xy+2y^{2}}-5=0\\\\\frac{x^{2}+3xy+11y^{2}-5xy-10y^{2}}{xy+2y^{2}}=0\\\\\frac{x^{2}-2xy+y^{2}}{xy+2y^{2}} =0\\\\\frac{(x-y)^{2}}{y(x+2y)}=0\\\\\left \{ {{x-y=0} \atop {x\neq0;x\neq-2y }} \right. \Rightarrow x=y$

$\frac{x^{3}-2xy^{2}-3x^{2}y+7y^{3}}{x^{3}-2y^{3}}=\frac{x^{3}-2x*x^{2}-3x^{2}*x+7x^{3}}{x^{3}-2x^{3}}=\frac{x^{3}-2x^{3}-3x^{3}+7x^{3}}{-x^{3}} =\frac{3x^{3}}{-x^{3}}=-3\\\\Otvet:\boxed{\frac{x^{3}-2xy^{2}-3x^{2}y+7y^{3}}{x^{3}-2y^{3}}=-3}$