8.3
Multiplying Polynomials
I got polynomials….
They’re multiplying!
And I’m losing a
binomial. Cause the
power you’re
supplyin’, it’s
terrifyin’.
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.
Homework Quiz
Simplify the following expression:
−3𝑤(𝑤 2 + 7𝑤 − 9)
Let’s Think About It!
• Is the following statement true?
𝑥 + 4 𝑥 + 5 = 𝑥 2 + 20
• Take out a scratch piece of paper and write down
your thoughts. You have 2 minutes! 
– Think about ways that you could check it.
– Make a decision: Yes or no?
• Defend your answer with 2-3 sentences.
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
Not just one number in front!
must do it twice!
– Example: (4x – 9)(2x + 7)
• We need to distribute all of the numbers in the first
grouping to each of the numbers in the second
grouping
How do I multiply
Polynomials?
(a + b)(c + d)
a(c + d) + b(c + d)
ac + ad + bc + bd
Two Paths to Take…YOU CHOOSE! 
Let’s Take a Look Back at…
(4x – 9)(2x + 7)
DISTRIBUTING
BOX METHOD
Example 1: TOGETHER
Find the product.
(x + 4)(x - 5)
Example 2: TOGETHER
Find the product.
(3a + 4)(2a + 1)
Practice 1: YOU TRY!
Find the product.
(c - 3)(2c - 5)
Practice 2: YOU TRY!
Find the product.
(2w + 3)(2w - 3)
How do I multiply by a
trinomial???
(a + b)(c + d + e)
a(c + d + e) + b(c + d + e)
ac + ad + ae + bc + bd + be
Example 3: TOGETHER
Find the product.
(t2 + 6t – 8)(t – 6)
Practice 3: YOU TRY!
Find the product.
(3a + 4)(a2 – 12a +1)
Practice 4: YOU TRY!
Find the product.
(n + 1)(3n2 +2n+5)
Real World Example
GEOMETRY The area of a
rectangle is the measure of
the base times the height.
Write an expression for the
area of the rectangle.
Homework!
8.3 Practice Worksheet