Question 1199800
You may be trying to show what is equivalent to this:

{{{((y^2-y-6)/(y^2-25))/((3-y)/(5-y))}}}



You can factor quadratic trinomials and difference of squares?  

This works better on paper than through pure text, keyboard, and rendering tags.



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Very obviously, about 1,
any real nonzero a,  {{{a/a=1}}}, or a and b real nonzero numbers,  {{{(a+b)/(a+b)=1}}}.  
for factor {{{-1}}},
{{{-1(a-b)=-1a-(-1)b=-a+b}}}.