Question

How do you solve `8^(-2-x)=431`?

Answer 1

`x=-4.9172`

Explanation:

As from definition of log `a^m=b` implies `log_a b=m`

Also `log_a b=logb/loga` where `log` without mentioning base means logarithm to the base `10` and we can get this from tables.

`8^(-2-x)=431` means `log_8 431=-2-x`

or `-2-x=log431/log8=2.6345/0.9031=2.9172`

Hence, `x=-2-2.9172=-4.9172`