Monday 24 February 2014

LOGARITHMS B34


If logx625 + log381 = 8; find x

solution

logx625 + log381 = 8

logx625 + log334 = 8

logx625 + 4log33 = 8

logx625 + 4 x 1 = 8

logx625 + 4 = 8

logx625 = 8- 4

logx625 = 4

625 = x4

54 = x4      Powers cancel out

x = 5


Hence x = 5.

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