# How do you evaluate #log_7 343#?

##### 1 Answer

Aug 7, 2016

#### Explanation:

It is very useful to know all the powers up to 1000 by heart.

There are not that many and it makes any question with powers and exponents so much easier to do.

"Which power of 7 is equal to 343?"

OR "How do I make 7 into 343?"

The powers of 7 are:

Therefore

If we do not know this we can use the log change of base law:

Or the longer method..

It really is just easier to learn the powers by heart, as part of your basic maths general knowledge!