You bought 4 books in addition to the tote bag.
Explanation
Suppose, the number of books you bought was [tex]x[/tex]
Each book costs $3.50
So, the total cost of [tex]x[/tex] number of books will be: [tex]\$3.50x[/tex]
Given that, the tote bag costs $5 and you spend a total of $19 before taxes. So, the equation will be.....
[tex]3.50x+5=19\\ \\ 3.50x=14\\ \\ x=\frac{14}{3.50}=4[/tex]
So, you bought 4 books in addition to the tote bag.
