Chapter 2 - Solving Equations - 2-1 Solving One-Step Equations - Practice and Problem-Solving Exercises - Page 85: 50

c=23 CD's

First, let's name "c" as the variable in this problem because c is the current number of CD's. The rack can fit 30 CD's when full and can then add 7CD's to the rack before it's full, which is shown as: c+7=30. Now, we need to get c by itself by subtracting 7 from both sides, which is shown like this: (c+7)-7=30-7 c=23CD's