Go Down

Topic: [Solved] X as the exponent (Read 4147 times) previous topic - next topic


JimboZA had it right way back in the first reply.
Take logs of both sides, take the exponent to the front, solve for exponent

See "rule 4" here: http://www.mathwords.com/l/logarithm_rules.htm

5 ^ X = 18
log(5^x) = log(18)
x * log(5) = log(18)
x = log(18)/log(5)

Or you can think:
5^x = 18
logbase5(5^x) = logbase518
x = logbase518
and then use the "change of base" forumla (rule 5 at the above page.)

Go Up