Cократите дробь:
а) 14х^4y/49xy^3=
б) 5х/x^2+3x=
в) x^2-y^2/2x-2y=
г) x^2-16/x^2-8x+16=

A) $frac{14 x^{4}y }{49x y^{3} }= frac{2 x^{3} }{7 y^{2} }$

б) $frac{5x}{ x^{2} }+3x= frac{5x+3 x^{3} }{ x^{2} }= frac{x(5+3 x^{2})}{ x^{2} }= frac{5+3 x^{2} }{x}$

в) $frac{ x^{2} - y^{2} }{2x-2y}= frac{(x-y)(x+y)}{2(x-y)}= frac{x+y}{2}$

г) $frac{ x^{2} -16}{ x^{2}-8x+16}= frac{(x-4)(x+4)}{(x-4)^{2} }= frac{x+4}{x-4}$