Can this (14xy-(1+y^2)(1+x^4 *y^2))/(7x^2 -2xy(1+x^4 *y^2)) be simplified to this (14xy-(1+y^2))/(7x^2 -2xy)? Yes or no explain why.

no. For the same reason that

(6 - 5*7)/(8-3*7) is not (6-5)/(8-3)