Parabolas with vertices not at the origin

Use the slope formula.



is your first x value and is your second x value.

Likewise,  is your first y value and  is your second y value.

4 is your first x value. 5 is your second x value.
-3 is your first y value. -6 is your second y value.

Plug in your x and y values.







Basically, the slope formula helps you find the change in x divided by the change in y. To find the change of one value to another, simply subtract. Subtraction will help you find the difference, or change, from one value to the other.

Your answer is C. -3. You can further prove this because for every unit you move left or right on the graph, you move down 3 units.

, or 

Additionally, a negative graph always points downwards, which is what your graph is doing.