2. By: Dr. Julia Arnold

3. Composition is a binary operation like addition, subtraction, multiplication and division are binary operations. (meaning they operate on two elements) f+g f-g fgfg The composition symbol is: Thus

5. The easiest way to describe composition is to say it is like substitution. In fact Read f of g of x which means substitute g(x) for x in the f(x) expression.

6. For example: Suppose f(x)= 2x + 3, and g(x) = 8 - x Then Means substitute the g function for x in the f function… like this f(x)= 2x + 3 f(g(x) )= 2 g(x) + 3

7. f(x)= 2x + 3, and g(x) = 8 - x f(x)= 2x + 3 f(g(x) )= 2 g(x) + 3 Now substitute what g equals for g(x) f(8 - x)= 2 (8 - x) + 3 = 16 - 2x + 3 = 19 - 2x So, = 19 - 2x

8. An interesting fact is that most of the time. Let’s see if this is the case for the previous example.

9. f(x) = 2x + 3, andg(x) = 8 - x Thus we will substitute f into g. g(x) = 8 - x g(f(x) ) = 8 - f(x) Now substitute what f(x) is: g(2x + 3) = 8 - (2x + 3) = 8 - 2x - 3 = 5 - 2x

11. Let and

12. Write the f function Substitute g(x) for x Replace g(x) with Simplify Step 1 Step 2 Step 3 Step 4

13. Find: When ready click your mouse. The answer is: A) B) Move your mouse over the correct answer.

14. Find: When ready click your mouse. The answer is: B) A) Move your mouse over the correct answer.

15. Find: When ready click your mouse. The answer is: B) A) Move your mouse over the correct answer.

16. A) Ans. A for the previous example Was actually

17. Do the practice problems following This module in your module section Of Blackboard. Check your work using This live math page.live math