You take the total cost ($747.62) and multiply it by .10 (discount in decimal form) which equates to 74.762 (round to 74.76) and then subtract the total cost by the discount price ($672.86) and then multiply that number by the sales tax (.06). That should give you 40.3716, round to $40.37. Add that sales tax to the discounted total, which gives you $713.23
The answer is $713.23