Question

Оооочень срочно, 9задание

Answer 1

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

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

Ответ: $12$

Answer 2

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