If the function graphed is f(x), find f(1).
a) -4
b) -1/4

c) 0
d) 4

choice A) -4



Step 1) Draw a vertical line through 1 on the x axis

Step 2) Mark the point where the vertical line and the blue curve intersect (or cross each other)

Step 3) Draw a horizontal line through the point marked in step 2. Note how this horizontal line goes through -4 on the y axis. 

So the point (1,-4) is on the blue curve. This means if x = 1 is the input then y = -4 is the output. Recall that y = f(x). So f(x) = -4 is the output as well when the input is x = 1.

In short, this is why f(1) = -4