а/в -1 =а-в/в

8/х^2-3/х+2=8-х(3+2х)/х^2

5-4 m+5n/n=10n-4m/n

4c+3/c-1-3=c+6/c-1

a^2+b^2/2a-b+2a+b=5a^2/2a-b

m-25/m-5 - 5=m(m-5)/m-5