General Mathematics Lesson 2 (Evaluating Functions).ppt

Evaluating Functions

3. Functional Notation
An equation that is a function may
be expressed usingfunctional
notation.
The notationf(x)(read “fof(x)”)
represents the variable y.

4. Example:
y= 2x+ 6 can be written as f(x) = 2x+ 6.
Given the equationy= 2x+ 6, evaluate when x= 3.
y= 2(3)+ 6
y= 12
Functional Notation Cont’d

5. For the function f(x) = 2x+ 6, the notation f(3)
means that the variable xis replaced with the
value of 3.
f(x) = 2x+ 6
f(3) = 2(3) + 6
f(3) = 12
Functional Notation Con’t

6. Given f(x)= 4x + 8, find each:
1.f(2)
2. f(a +1)
3. f(4a)
Evaluating Functions
= 4(2) + 8
= 16
= 4(a+ 1) + 8
= 4a+ 4 + 8
= 4a+ 12
= 4(-4a) + 8
= -16a+ 8

7. For the function f(x)= -5x + 11, determine:
a)f(1)
b)f(-3)
c)f(0)
= -5(1) + 11
= -5 + 11
= 6
= -5(-3) + 11
= 15 + 11
= 21
= -5(0) + 11
= 0 + 11
= 11

8. Determine the value of x when given f(x).
Given f(x)= 2(4x + 8), determine x
when:
f(x) = 2 f(2)
f (x) = -1 f(-1)
= 2{4(2) + 8}
= 2(8 + 8)
= 2(16)
= 32
= 2{4(-1) + 8}
= 2(-4 + 8)
= 2(4)
= 8