1. 10.2 – Multiplying Polynomials
Oh, you better distribute. Cause I need an answer. And my calculator just won’t do. Yeah, you better distribute, you better understand, to my math, I must be true.
I got polynomials…. They’re multiplying! And I’m losing a binomial. Cause the power you’re supplyin’, it’s terrifyin’.

2. Warm-Up Simplify the following expressions. (x + 4)2 -3(2 – 5x)

3. Homework Answers
20) -4; quadratic, trinomial 22) 5; quadratic, trinomial 24) 14; quartic, binomial 26) 7.4; cubic, binomial 28) 9; cubic, polynomial
30) -95; quartic, polynomial
32)
34)
36)
38)

4. Journal Entry Is the following statement true?
Answer this question in journal form in your notebook.
Think about ways that you could check it.
Make a decision: Yes or no?
Defend your answer with 2-3 sentences.
Tweet about it later: #mathswagg

5. Discovery Activity ***REMEMBER: AREA = LENGTH X WIDTH***
Find the area of the large rectangle below!
5x cm
8 cm
2x cm
3 cm
***REMEMBER: AREA = LENGTH X WIDTH***

6. Solution
(5x + 8)(2x + 3) = 5x·2x + 5x·3 + 8·2x + 8·3 = 10x2 + 15x + 16x + 24 = 10x2 + 31x + 24
5x cm
8 cm
10x2
16x
2x cm
3 cm
15x 24

7. Multiplying Polynomials Using The Distributive Property
Remember doing something like: 3(x - 5)?
This became: 3(x) + 3(-5)
Which simplified to 3x - 15
Now we are dealing with situations where we must do it twice!
Example: (4x – 9)(2x + 7)
We simplify need to distribute all of the numbers in the first grouping to each of the numbers in the second grouping
Not just one number in front!

8. General Rule
(a + b)(c + d)
a(c + d) + b(c + d)
ac + ad + bc + bd

9. Example 1: iDo
Find the product.
(3a + 4)(2a + 1)

10. Example 2: iDo
Find the product.
(x + 4)(x - 5)

11. Example 3: WiiDo
Find the product.
(c - 3)(2c - 5)

12. Example 4: WiiDo
Find the product.
(2w + 3)(2w - 3)

13. Example 5: YouDo
Find the product.
(y + 5)(y + 7)

14. Example 6: YouDo
Find the product.
(3x - 5)(5x + 2)

15. So what if there’s a trinomial?
(a + b)(c + d + e)
a(c + d + e) + b(c + d + e)
ac + ad + ae + bc + bd + be
(a + b + c)(d + e)
a(d + e) + b(d + e) + c(d + e)
ad + ae + bd + be + cd + ce

16. Last Example
Find the product.
(t2 + 6t – 8)(t – 6)

17. Boss/Secretary Practice
Students will work in pairs.
Materials: One worksheet, one calculator, one pencil per pair
Students will be given one of two roles (you will alternate these roles):
Boss: Tells the secretary how to solve the problem, is the only one talking in the pair, does not write anything
Secretary: Listens to the boss, writes everything, cannot talk unless (s)he is helping the boss
Complete the worksheet in next before the end of class!

18. Homework pg. 587 #18-46 every other even
(#18, 22, 26, 30, 34, 38, 42, 46)