Question

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

Answer 1

Нифига это какой класс?

Answer 2

x²-xc+2xy-yc+y²=(x²+2xy+y²)-(xc+yc)=(x+y)² - c(x+y)=(x+y)(x+y-c)

xy+xc-c² +y² =(xy+xc)-(c²-y²)=x(y+c)-(c-y)(c+y)=(c+y)(x-c+y)=
=(c+y)(x+y-c)

$frac{(x+y)(x+y-c)}{(c+y)(x+y-c)}= frac{x+y}{c+y}$