Question from http://www.sgforums.com/forums/2297/topics/313896
Use indices to solve the following:
3y = 6z show that z = (xy)/(x+y)
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Answer:
2x = 6z => 2(1/z) = 6(1/x) ------ (1)
3y = 6z => 3(1/z) = 6(1/y) ------ (2)
(1) * (2):
2(1/z) * 3(1/z) = 6(1/x) * 6(1/y)
6(1/z) = 6(1/x + 1/y)
thus
1/z = 1/x + 1/y
rearranging
z = (xy)/(x+y)
