Question

How do you solve for x in `6 = 15^(1-x)`?

Answer 1

Use logs to calculate: `x = 0.338`

Explanation:

The variable is in the index and 6 is definitely not a power of 15, therefore logs are called for...

Log both sides: `log 6 = log 15^(1-x)`

Power law: #log 6 = (1-x) log 15

isolate (1-x): `(log6)/(log15) = 1-x`

With a calculator: `1-x = 0.6616`

                             #0.338 = x#