Question

Оооочень срочно, 9задание

Answer 1

$\frac{6x^2y^2}{x+y} \cdot(\frac{1}{y^2} -\frac{1}{x^2})=\frac{6x^2y^2}{x+y} \cdot(\frac{x^2-y^2}{x^2y^2} )=\frac{6x^2y^2\cdot(x-y)(x+y)}{(x+y)\cdot x^2y^2} =6(x-y)$

Если $x=\sqrt{7}+2;y=\sqrt{7}$, то $6(x-y)=6(\sqrt{7}+2-\sqrt{7})=12$

Ответ: $12$

Answer 2

$\frac{6x^{2}y^{2}}{x+y}*(\frac{1}{y^{2} }-\frac{1}{x^{2} })=\frac{6x^{2}y^{2}}{x+y}*\frac{x^{2}-y^{2}}{x^{2}y^{2}}=\frac{6(x+y)(x-y)}{x+y}=6(x-y)\\\\6(\sqrt{7}+2-\sqrt{7})=6*2=12$