Solve for x if 2^x+1 = 5 using log tables the log table is a 4 digit log table from 1.0-9.9

2 Answers | Add Yours

sciencesolve's profile pic

sciencesolve | Teacher | (Level 3) Educator Emeritus

Posted on

You need to isolate `2^x`  to the left such that:

`2^x = 5 - 1 =gt 2^x = 4`

You need to write 4 as `2^2`  such that:

`2^x = 2^2`

You should take logarithms of base 2 both sides such that:

`log_2 (2^x) = log_2 (2^2)`

`x*log_2 (2) = 2*log_2 (2)`

You need to remember that `log_2 (2) = 1`  such that:

`x*1 = 2*1 =gt x = 2`

Hence, evaluating the solution to equation yields x = 2.

thilina-g's profile pic

thilina-g | College Teacher | (Level 1) Educator

Posted on

`2^x+1 = 5`

`2^x = 4`

`log_(10)(2^x) = log_(10) 4`

`x log_10 2 = log_(10) 4`

`x xx 0.3010 = 0.6020`

`x = 0.6020/0.3010`

`x =2`

 

Therefore x =2.

 

We’ve answered 318,929 questions. We can answer yours, too.

Ask a question