Yay! The most fun stuff. You can divide the first 25x5y4 by 5x4y4 since they have the same terms. 25/5 is 5. X5/x4 is x. And the y cancels out. So u are left with 5x in the numberator
Now do the same with the other guy in the numberator -10x4y3. -10/5 is -2. X4/x5 is x^-1 (so move the x to the denominator and it will just be x) and the same with the y move y^-1 to the denominator. Your answer is 5x-2 over xy
I really hope this is right!