Question

кто знает ??????????

Answer 1

$dfrac{2x^2-7y}{x+y}- dfrac{x^2-7y+y^2}{x+y}= \ = dfrac{2x^2-7y-(x^2-7y+y^2)}{x+y}= \ = dfrac{2x^2-7y-x^2+7y-y^2}{x+y}= \ = dfrac{x^2-y^2}{x+y}= \ =dfrac{(x+y)(x-y)}{x+y}= \ =x-y$