How do you solve 3x=729?

2 Answers
Jan 17, 2017

Multiply each side by log10 . Eventually, x = 6

Explanation:

Usually, just log means log10, so we can multiply both sides by log.
log3x=log729
Then, with the log law, we can move the exponent x to the left of log3.
xlog3=log729
Since the x is attached by multiplication, we can divide both sides by log 3.
x=log(729)log(3)
Plug into your calculator and voila!
x=6

I used log since this question was posted in log, but you could also solve by making 729 base 3, then set the exponents equal to each other.
3x=36
x=6
You could also say x=log3(729) (by using the log function) and plug that into your calculator as well.

Aug 5, 2018

x=6

Explanation:

We can rewrite 729 as 36. With this in mind, we now have

3x=36

Since the bases are the same, we can equate the exponents. We get

x=6

Hope this helps!