Solve the equation 5^x = 8, giving your answer to 3 significant figures.

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Since there is an x written as a power here, it suggests that this question should be solved using logs (here assume I am using the natural logarithm, which has base e). Taking logs of both sides of the equation gives log5x = log8

Using the rule logab = bloga, the equation becomes xlog5 = log8

If we then divide the equation through by log5, we see that x = log8/log5 = 1.29

Hannah M. A Level Maths tutor, GCSE Maths tutor, 11 Plus Maths tutor

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