# Given a set # {-3,2,-1,x} #, for what x would the mean of the set be -5?

##### 1 Answer

Jan 5, 2016

#### Explanation:

or, "the sum of all the elements divided by the number of elements"(as we're talking about a set here.)

We already know the mean is

So adding together all our elements and dividing by how many there are, should give us a mean of

so