adding rational expressions

ash1017

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Apr 7, 2008
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The problem I am working on is a(squared) divided by (a-b) plus b(squared) divided by (b-a). I have already taken the b(squared) divided by (b-a) times -1 to get a common denominator. I get a different answer than the back of the book. i do not understand what i am doing wrong. I also have one more question. i will post once this one is answered.
 

stapel

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ash1017 said:
The problem I am working on is a(squared) divided by (a-b) plus b(squared) divided by (b-a).
I will guess that you mean the following:

. . . . .[(a[sup:2oxwyks8]2[/sup:2oxwyks8])/(a - b)] + [(b[sup:2oxwyks8]2[/sup:2oxwyks8])/(b - a)]

I will guess that the instructions were something along the lines of "simplify the expression". But I'm afraid I don't understand what you did...? (It helps to show your work, rather than just mention that you did it. Until we can see what you did, it is difficult, if not impossible, to locate the errors, if any.)

A good first step would be to flip the subtraction in the second fraction's denominator to get:

. . . . .[(a[sup:2oxwyks8]2[/sup:2oxwyks8])/(a - b)] - [(b[sup:2oxwyks8]2[/sup:2oxwyks8])/(a - b)]

Since the fractions have a common denominator, add them. Factor the numerator, and cancel the common factor. (I don't know what answer you got, nor what the book is telling you, so I cannot comment on that. Sorry.)

Please reply with your work and reasoning so far. Thank you! :D

Eliz.
 
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