Question 268901
solve this equation for b?.... 
i/a+i/b=3/c 
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Subtract i/a from both sides
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i/b = 3/c-(i/a)
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Simplify the right side:
 i/b = (3a-ic)/(ac)
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Invert both sides:
b/i = (ac)/(3a-ic)
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Multiply both sides by "i":
b = (aci)/(3a-ic)
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Cheers,
Stan H.