Okay so 6.5% of $14.95 is 0.97175. That rounds to 0.97. And to get the total we just add 0.97 to 14.95. Our answer is 15.92. However if you don't want to round then you would add 14.95 and 0.97175 . This would give you15.92175. Hope this helps!
You can try by plugging each ordered pair and seeing if the equation comes out true.
(5, 1)
2 * 5 - 1 = 9
That's correct so C is the correct answer.