SOLUTION: Montrose and Salem are 10 miles apart. Karen lives 12 miles from Salem. What are the possible distances Karen lives from Montrose?

 
Let the point M be Montrose and the point S be Salem



Since Karen lives 12 miles from S, we'll draw a circle with center S 
and radius 12 miles:



Karen lives somewhere on that 12 mile radius circle. Let's draw in the 
complete horizontal diameter of that circle, and label its endpoints A
and B:



The closest Karen could live to M is 2 miles if she lives at A.
The farthest Karen could live from M is 22 miles if she lives at B.

Therefore she lives 2 miles or more from Montrose and 22 miles or 
less from Montrose.  So if her home's distance from Melrose is 
represented by the letter D, then the inequality is

      2 < D < 22

Edwin