Question

How do you solve and write the following in interval notation: `-7<b/9<0`?

Answer 1

See explanation.

Explanation:

To solve such double inequality you can use all methods used in standard inequalities only remembering to use them for all sides. Here you can multiply all sides by `9`:

`-7 < b/9 < 0` ##

After multiplying by `9` you get:

`-63 < b < 0`

The numbers fulfilling the inequality are greater than `-63` and smaller than `0`, so the solution can be written as:

`b in (-63;0)`