Question

How do you solve `-9< 3n < 18`?

Answer 1

`-3 < n < 6`

Explanation:

`color(blue)"Isolate"` n in the middle interval and have numeric values in the 2 outer intervals.

divide ALL 3 intervals by 3

`(-9)/3 < (cancel(3) n)/cancel(3) < 18/3`

`rArr-3 < n < 6" is the solution"`

Answer 2

Divide all terms by `3` to solve for `n`.

`-3 < n < 6`

Explanation:

Dividing by a positive does not affect the inequality signs.

`-9/3 = -3`

`(3n)/3 = n`

`18/3 = 6` so

`-3 < n < 6`