Is this relation a function?

The parabola x= √y-9 opens: a.)up b.)down c.)right d.)left

Scrub a dub toothbrushes are $4.00 each. there is a 10% discount, but there is also a 6% sales tax after the discount is applied. what is the new price after tax? round to the nearest penny

Combine the information in the problem and the chart using the average balance method to solve the problem.