Questions about the world of GRE Math from other sources and general math related questions.
Lionheart3239
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Simplify

by Lionheart3239 Tue Feb 09, 2016 5:07 pm

1/((1/x)+1) =
1/((x+1)/x) =
x/(x+1)

Please someone explain how to get from step 1 to step 2, i understand the x goes on top in step 3.
tommywallach
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Re: Simplify

by tommywallach Thu Feb 11, 2016 3:25 pm

They're rewriting the 1 in the denominator (the "+1" part) as x/x. This gives it a common denominator with the 1/x part, and then we can just add the numerators.

-t

P.S. I always encourage my students not to say things like "the x goes up top." This kind of thinking confuses arithmetic. Always think in terms of multiplication, division, addition, and subtraction. I don't even like the term "cancel," which muddies the clarity of the operation.
Lionheart3239
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Re: Simplify

by Lionheart3239 Wed Feb 17, 2016 5:06 pm

Thank you for your explanation and reply back.
tommywallach
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Posts: 1917
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Re: Simplify

by tommywallach Sat Feb 20, 2016 4:03 pm

No problem!