Question

Сократите $frac{ x^{2} -xc+2xy-yc+ y^2}{xy+xc- c^{2}+ y^{2} }$

Answer 1

$frac{x^2-xc+2xy-yc+y^2}{xy+xc-c^2+y^2}= frac{(x^2+2xy+y^2)-(yc+xc)}{(xy+xc)-(c^2-y^2)}= frac{(x+y)^2-c(y+x)}{x(y+c)-(c-y)(c+y)}=$$=frac{(x+y)(x+y-c)}{(y+c)(x+y-c)}= frac{x+y}{y+c}$