Question

How do you solve `23^x + 5 = 128`?

Answer 1

`x = ln(123)/ln(23) = log_23(123)~~1.535`

Explanation:

Using the property that `ln(a^x) = xln(a)`, we have

`23^x+5 = 128`

`=> 23^x = 123`

`=> ln(23^x) = ln(123)`

`=> xln(23) = ln(123)`

`:. x = ln(123)/ln(23) = log_23(123)~~1.535`