# [SOLVED]logarithm

#### siyanor

##### New member
I have an equation which answered it in two ways,which one is correct ?

#### SuperSonic4

##### Well-known member
MHB Math Helper
I have an equation which answered it in two ways,which one is correct ?
View attachment 163
The first method is not correct because ln(7.3) has simply disappeared.

The second method is correct but the rounded answer is not correct. $x = \frac{1}{2}\left(\frac{\ln(10)}{\ln(7.3)}-1\right) \approx 0.0792$

#### checkittwice

##### Member
I have an equation which answered it in two ways,which one is correct ?View attachment 163
$$7.3^{2x + 1} \ = \ 10$$

siyanor,

(regarding the correct process of method #2),
because you have 10 on one side at that point,
that lends itself to taking log (base 10) of each
side:

$$\log_{10}7.3^{2x + 1} \ =$$$$\log_{10}10$$

$$(2x + 1)\log(7.3) \ = \ 1$$

$$2x + 1 \ = \ \dfrac{1}{log(7.3)}$$

And continue . . .