$671.68
1) In this problem, examining that table let's pick the price of that TV.
Price: $ 729.99
Discount (50 -55") : 15% off
Tax: 8.25%
Total
2) Since the discount is 15% let's subtract 0.15 from 1
729.99 (1 -0.15) This 1 is equivalent to 100%
729.99(0.85)
620.49
Charging the Tax Sale: 8.25 or 0.0825
620.49 (1 + 0.0825) Since the tax makes it more expensive
620.49(1.0825)
671.68
3) Hence, the cost of that 50" TV will be $671.68