A research study asked 2208 homeowners how many bedrooms were in their homes. The results are shown in the table below. What is the probability that a homeowner chosen at random has 3 bedrooms?​

To find out what the x value is at this specific point, all you have to do is input the y value into the equation. 

If you do this, it becomes:

-2 = -2x + 4 (y is inputed into the equation)
-2x = -6 (you minus 4 from both sides)
x = 3 (divide both sides by -2)

Hence the missing value is 3, Coordinates are therefore (3, -2)