The price of a pair of headphones is $39.99 before tax. dalton bought the headphones for 30% off. he then paid 6% sales tax on the discounted price.

part a: how much did dalton pay in sales tax? show all work and steps in your solution.
part b: what is the total amount that dalton paid for the headphones? show all work and steps in your solution.

$39.99x.3=$12
$39.99-12=$27.99
$27.99x.06=$1.68(sales tax)
$27.99+$1.68=$29.67(total price of headphones)

So the first thing we do is to multiply the top equation by 3. the reason i want to do this is i notice there will be a 6y on both equations and can possibly add/subtract them. so we get 6y = -3x + 27. adding that and the second equation we get 6x = 27-15 which is 12. divide by 6 and we get 2. ∴ x = 2. substituting 2 into the first equation we get 2y = -2 + 9 which is 7. divide by 2 and we get 7/2. ∴ y = 7/2, x = 2.