For teaching resource

1. Evaluating Functions

2. Learning objectives:
•At the end of the learning session,
you should be able to evaluate of
functions.

3. Recall:

4. Use of function in real-life situation
•Counting the number of window glass in the
classroom using a functional model.
W(x) = 8x
If x = 6
Then,
W(6) = 8(6) = 48
Therefore:
There are 48
Glasses in the
room.

5. Evaluating functions
Given:
f(x) = x + 5 and g(x) = 2x – 1
If x = 3
Then,

6. Alternative solution
(f+g)(x) = x + 5 + 2x – 1
= 3x + 4
Evaluating the result,
(f+g)(3) = 3x + 4
= 3(3) + 4
= 9 + 4
= 13

7. Evaluating functions
Given:
f(x) = x + 5 and g(x) = 2x – 1
If x = 3
Then,

8. Alternative solution
(f-g)(x) = x + 5 – (2x – 1)
= -x + 6
Evaluating the result,
(f-g)(3) = -x + 6
= -(3) + 6
= 3

9. Activity 1.
Given:
h(x) = x + 2 and v(x) = 3x + 1
Find the following and evaluate if x = 4:
1.(h + v)(x)
2.(h – v)(x)
3.(h • v)(x)
4.(h ÷ v)(x)

10. Activity 2.
Punch line

11. Essay Writing:
•Guide questions:
1. How to evaluate functions?
2. Can you evaluate the final result after doing
the operation like adding two functions?
3. Which is more convenient to do, substituting
the value of “x” before doing the operation or
do the operation before substituting the value
of “x”?

12. RUBRICS FOR WRITTEN
WORK (ESSAY) RAW
SCORE
INDICATORS
5
Write the essay nicely and it has
appropriate content related to the topic.
4
Correct and appropriate but lack of
neatness.
3
Wrong use of capitalization, punctuation
marks, indention, etc.
2 Incomplete work.
1 Obviously copied the work of others.
0 No submitted work.