Chapter 1, Equations and Inequalities - 1.2 Evaluate and Simplify Algebraic Expressions - 1.2 Exercises - Quiz for Lessons 1.1-1.2 - Page 16: 13

$100-8n$ $52 remains after purchasing 6 CDs

We know that for each CD we buy, the amount of money on the gift card decreases by 8 dollars. So after buying $n$ CDs, we lose $8n$ dollars. From this we derive the expression $100-8n$. Since we bought 6 CDs, all we need to do is plug $n=6$ into the expression: $100-8n$ $=100-(8\times6)$ $=100-48$ $=52$