Here, the equation of parabola is: (-36y)=x^2
The standard form of parabola is:
(X-h)^2=4p(y-k).
According to given equation, vertex = (0,0) and p = -9
This a vertical parabola opening down, because p = -9 here.
Therefore ditectrix will be y= -9
Okay, let's find out how much the tax was by finding out what 7% of $28 is, we do this by multiplying:

Convert 7% into a decimal, we do this by dividing it by 100 because percentages are parts of 100:

Multiply:

So this is the tax. Add it to the original price to get the total price:
we have

we know that
If the point is an equation solution, it must satisfy the equation.
<u>case a</u>) 
Substitute the values of x and y in the equation


-------> the point is not solution of the equation
<u>case b</u>) 
Substitute the values of x and y in the equation


-------> the point is solution of the equation
<u>case c</u>) 
Substitute the values of x and y in the equation


-------> the point is not solution of the equation
<u>case d</u>) 
Substitute the values of x and y in the equation

-------> the point is not solution of the equation
therefore
<u>the answer is</u>
The point
is solution of the equation