SOLUTION: r=ab/a+b ;a solve for a

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Question 57746This question is from textbook mcdougal littell
: r=ab/a+b ;a solve for a This question is from textbook mcdougal littell

Found 2 solutions by stanbon, funmath:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
r=ab/(a+b) ;a solve for a
Cross-multiply to get:
ra+rb=ab
Get the "a's' on one side:
ab-ra=rb
Factor out the "a" to get:
a(b-r)=rb
a=rb/(b-r)
Cheers,
Stan H.

Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!
r=ab%2F%28a%2Bb%29 ;a solve for a
r%28a%2Bb%29=ab%28a%2Bb%29%2F%28a%2Bb%29 Multiply both sides by LCD.
ra%2Brb=ab Get all the a's on one side of the = sign
ra-ab%2Brb=ab-ab
ra-ab%2Brb=0 Get the things without a's on the other side of the = sign.
ra-ab%2Brb-rb=0-rb
ra-ab=-rb Factor out the a on the left.
a%28r-b%29=-rb Divide both sides by r-b.
a%28r-b%29%2F%28r-b%29=-rb%2F%28r-b%29
a=-rb%2F%28r-b%29 it could be written as: a=rb%2F%28b-r%29
Happy Calculating!!!