For $7.52 you purchased 8 pens and highlighters from a local bookstore. each highlighter cost $1.09 and each pen costs $0.69. how many pens did you buy?

Let x represent pens. Let y represent highlighters.

 x + y = 8

y = 8 - x

 1.09y + .69x = 7.52        

 Since we know y = 8 - x, we can replace the y in the equation.

 1.09(8 - x) + .69x = 7.52

8.72 - 1.09x + .69x = 7.52

8.72 - .4x = 7.52

-.4x = -1.2

x = 3

You bought 3 pens.

hope this helps!