9. you go to a local mechanic to get your tires changed. there is a 6% sales tax, but you get a 10% discount. a. write a function, t(x) for the total purchase amount after taxes but before discounts and fees. b. write a function, d(x) to account for the total after discounts on purchase amount x. c. does it matter whether the mechanic adds the tax first or takes the discount first? show all your work to verify.