Question

What is the solution of log2x-7(81) = 4

2x-7 is subscript

Answer 1

x=5

Explanation:

`log_(2x - 7)(81) = 4`

Raise both sides with a base of 2x-7

`81 = (2x - 7) {}^(4)`

We get two solutions

`3 = (2x - 7)`

`10 = 2x`

`x = 5`

The other solutions is

`- 3 = 2x - 7`

`4 = 2x`

`x = 2`

The solution x=2 wont work since it will make our base negative.

So the answer is 5