Q: Evaluate f(3) for each of the following:
a) (1,2) (2,0) (3,1) (4,2)
b) (1,2) (2,3) (3,4) (4,5)
A: Something to remember about functions… The general notation is “f(x)”. So, if I ask for f(3), I am implying that x is 3. Notice that the 3 took the place of the x? Basically:
f(3) means: plug in 3 for x and what is the y value? Or, which number “pops up” when x = 3.
Answer for part A: Notice that these are all (x, y) points… Which point has x=3? That is the point (3, 1). So, f(3) = 1.
Answer for part B: x = 3 at the point (3,4). So, f(3) = 4.
