How do you solve $log x + log 4 = 2$ ?

Question

11317 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-01-25T20:10:46

The answer is $x=25$

$logx+log4=2$

First we use the identity which says that: $loga+logb=log(a*b)$

$log(4x)=2$

Then we change the number on the right side to a logarythm using a formula:

$a=log_b(b^a)$

$log(4x)=log100$

Now we can skip the logarythm signs because both sides are single logarythms with the same base.

$4x=100$

$x=25$

How do you solve log x + log 4 = 2log x + log 4 = 2?