This document provides examples and explanations for multiplying binomials using the double distributive method. It begins with examples showing the multiplication of various binomials using algebra tiles. Students are asked to observe the pattern and propose a rule. The document then states the double distributive method rule to distribute both terms from the first binomial to the second binomial and combine like terms. Finally, students are given three practice problems to multiply binomials using the new method.
3. Anticipatory Set
Find the following area.
(x + 3)
(x + 2)
2 x
x 1
1.) What are the dimensions of the algebra tiles above?
3
4. (x + 3)(x + 2)
REMOVED
PIECES
2 x
x x
x
x
1 1 1
x
1 1
1
2 2 x x 1 1
x x
4
5. (x - 3)(x + 3)
REMOVED
PIECES
2
x
x
x
x x x
x
1 1
1
1 1
1
1 1
1
2 2 x x 1 1
x x
5
6. (x - 1)(x - 4)
REMOVED
PIECES
2
x
x
x
1
x
1
x
1
x
1
2 2 x x 1 1
x x
6
7. (x + 2)(x - 3)
REMOVED
PIECES
2
x
x
1
1
1
1
1
1
x
x
x
x
2 2 x x 1 1
x x
7
8. Conjecture: Based on the examples we have
completed, how would you multiply binomials
if you did not use the clips? (We are
creating an algebraic method)
8
9. (x + 5)(x + 2)
REMOVED
PIECES
2 2 x x 1 1
x x
9
10. (2x - 1)(x + 2)
REMOVED
PIECES
2 2 x x 1 1
x x
10
11. (x + 2)(x - 4)
REMOVED
PIECES
2 2 x x 1 1
x x
11
12. Rule:
Double Distributive Method: Distribute
both terms from the first binomail to the
second binomial. Simplify by combining like
terms.
(x + 3)(x - 2)
12
14. BEFORE YOU LEAVE
How close were you to the real rule when you created your personal
rule based on the work with the algebra tiles?
What steps did you not put in your rule?
Was there any parts of your rule that were unnecessary?
14
16. AIM: Multiplying Binomials
Rule:
Double Distributive Method: Distribute
both terms from the first binomail to the
second binomial. Simplify by combining like
terms.
1.) (x + 3)(x - 2)
2.) (x - 7)(x + 4)
3.) (x - 6)(3x - 9)
16
