if [a = d/b + d/c] then [d = a / (1/b + 1/c)]  TOPIC_SOLVED

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if [a = d/b + d/c] then [d = a / (1/b + 1/c)]

Postby gcmky on Mon May 23, 2011 8:39 pm

I have an equation that is a = d/b + d/c . Supposedly this means that
d = a / (1/b + 1/c) is also true. How do you get from the first equation to the second?
Someone told me to factor out d first but I'm not sure how. Thanks.
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Postby stapel_eliz on Mon May 23, 2011 10:48 pm

gcmky wrote:I have an equation that is a = d/b + d/c . Supposedly this means that
d = a / (1/b + 1/c) is also true. How do you get from the first equation to the second?
Someone told me to factor out d first but I'm not sure how. Thanks.

If you had "db + dc", would you be able to factor? :wink:
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Re:

Postby gcmky on Mon May 23, 2011 11:20 pm

stapel_eliz wrote:
gcmky wrote:I have an equation that is a = d/b + d/c . Supposedly this means that
d = a / (1/b + 1/c) is also true. How do you get from the first equation to the second?
Someone told me to factor out d first but I'm not sure how. Thanks.

If you had "db + dc", would you be able to factor? :wink:


Think I got it. Thanks.

a = d/b + d/c
a = d(1/b) + d(1/c)
a = d(1/b + 1/c)
a/(1/b + 1/c) = d(1/b + 1/c) / (1/b + 1/c)
a/(1/b + 1/c) = d
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Postby stapel_eliz on Mon May 23, 2011 11:29 pm

gcmky wrote:Think I got it. Thanks.

a = d/b + d/c
a = d(1/b) + d(1/c)
a = d(1/b + 1/c)
a/(1/b + 1/c) = d(1/b + 1/c) / (1/b + 1/c)
a/(1/b + 1/c) = d

Exactly! Good work! :wink:
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