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.