Hello!

To find the percent tax, use the equation:

Substitute in the given values:

Multiply by 100 to find the percent tax:

Answer:
A square.
Step-by-step explanation:
I plotted the points on Desmos and then connected them.
When connected, the lines form a square.
[Picture Below]
The central number in a geometric progression which indicates the central tendency or typical value of a set of numbers by using the product of their values as opposed to the arithmetic mean which uses their sum.
Answer: This equation does not have a vertex.
If the equation is not curved or composed of two straight lines it does not have a vertex.
If you need further explanation let me know. :)