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HW REVIEW
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13.3 FACTORING POLYNOMIALS
SWBAT FACTOR POLYNOMIALS
USING GCF, BOX, X AND X-BOX
METHODS.
GREATEST COMMON FACTOR (GCF)
In order to factor out a greatest common factor, use
the Distributive Property in REVERSE.
a(b + c) as ab + ac
FACTORING TRINOMIALS
BOX METHOD
1. Write the leading term (x2) and
the constant term (16) in the table.
2. Factor the leading term.
3. Find the factors of the constant term that add to equal term.
(1*16),(2*8),(4*4)
a. x2 + 9x +20
(x+5)(x+4)
b. x2 + 11x + 18
(x+9)(x+2)
X METHOD (when a=1)
-28
-24
-3
8
4
-7
5
-3
(x+8)(x-3)
(x-7)(x+4)
X-BOX METHOD (when a≠1)
a. 2x2 + 7x + 3
2*3=
6
6
1
7
x
3
2x
2x
6x
1
1x
2
3
(2x+1)(x+3)
• b. 2x2 + 3x - 5
5
2*-5=
-10
3
-2
2x
5
x
2x
5x
-1
-2x
2
-5
(2x+5)(x-1)
ANALYZING STUDENT WORK
Who factored the trinomial correctly? How? Who
factored incorrectly, what did they do wrong?
FACTOR
a. x2 - 9x - 10
b. 4x2 - 20x +16
c. -20 + 9b – b2
d. 3y2 - 8y - 3
(3y + 1)(y – 3)
e. 7x2 - 7x - 42
f. 3y3 - 27y2 - 30y