This document introduces the concept of functions and evaluating functions for given inputs. It defines three functions: f(x) = 2x + 1, g(x) = -x - 6, and h(x) = 4x - 2. It explains that writing a function like f(3) means to find the output of the function f when the input is 3, not f times 3. Then it provides examples of evaluating each function for different inputs.

2.  Find
y when x = 3.
y = 2x + 1
y = -x – 6
y = 4x – 2
 Which equation should you use?
 It doesn’t say…
So, we need names for our functions to
tell them apart!

3.  Instead
of y, we can say f(x).
 Read “f of x.”
 This means:
◦ The output value of function f when
the input is x
 Can
also use other letters (not just f!)
 f(x) = 2x + 1
 g(x) = -x – 6
 h(x) = 4x – 2

4.  When
we need to evaluate a function
for a given x value, it might say:
“Find f(3).”
This means:
Find the output when the input is 3.
It does NOT mean “f times 3”

5. x
f(x)
6
4
• Find f(6).
• f(9) =
•f(12) =
•f(15) =
9
7
12
10
15
13

6. t
g(t)
 Find:
 g(2)
 g(4)
 g(6)
1
2
2
4
3
6
4
8
5
10
6
12

7. x
h(x)
-2
-7
 Find:
 h(-2)
 h(1)
 h(-1)
-1
-5
0
-3
1
-1
2
1