Jamie purchased a DVD that was on sale for 15% off. The sales tax in her county is 5%. Let y represent the original price of the DVD. Write an expression that can be used to determine the final cost of the DVD.
First, she gets it on sale, so \(y-0.15y=0.85y\). Then, take that 0.85y and multiply it by 1.05 (to add the sales tax). So the result is \((0.85y)(1.05)=0.8925y\).