Answer:
$ 2.30
Step-by-step explanation:
Given that the sales tax rate 
The cost of the book is $ 12.99.
So, the tax on the book= 8.5% of 12.99

=1.10
So, the sales tax on the book is $ 1.10.
The cost of the video game is $ 39.99.
So, the tax on the book= 8.5% of 39.99

=3.30
So, the sales tax on the book is $ 3.40.
The difference of taxes on both the items = $ 3.40-$ 1.10=$ 2.30
So, the tax on the video game is $ 2.30 more than then tax on the book.