Hello everyone, I am stuck on my Mathematica homework. I am struggling to figure out how to add absolute value.

My problems are to solve inequality's using the reduce command. The next step I am supposed to solve the equation, using a "pretend equal" step, which I know how to do, but with absolute value I am unsure of.

For example, lets say a problem looks like

|3x-7| (less than or equal to) 21.

Am I supposed to break the equation up and do

Reduce[3x-7(less than or equal to) 21].

Reduce[3x-7(greater than or equal to) -21] ?

I looked into doing:

Reduce[Abs[3x-7](less than or equal to)21].

However, that gave a weird result.

If anyone could help me out I would appreciate it, the frustration is really starting to mount!