Question 65481
5a - 12    -   3a - 2
-------        -------
a^2-8a+15  -   a^2-8a+15

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The denominators are the same so subtract the numerators 
and write over the common denominator, as follows:
=[5a-12-(3a-2)]/[(a-3)(a-5)]
=[2a-10]/[(a-3)(a-5)]
=[2(a-5)]/[(a-3)(a-5)]
=2/(a-3)
Cheers,
Stan H.