Question

How do you solve and graph the compound inequalities `30 < 10u < 120`?

Answer 1

Remember you can perform the following operations on both sides of an inequality without changing the inequality:

• Add or subtract any number
• Multiply or divide by any positive (and non-zero) number

So
`30< 10u< 120`
can be simplified as
`3< u< 12`

The image below shows this relation graphed on a number line and in Cartesian space