Megan earns a rebate each month on completing surveys and books. she earns $0.75 for each survey she completes and $1 for each book. last month megan completed 8 surveys and earned $21.

part a: create an equation that will determine the number of books she purchased.
art

b: solve this equation justifying each step with an algebraic property of equality

part c: how many books did megan purchase last month?