Geometry
Review of Factoring
1. Greatest Common Monomial
 What can I divide every term by?
Examples:
 16x2 + 20xy + 8
Name _____________________
9x3 + 15x2 + 3x
2. Difference of Squares
 Two terms.
 Both numbers are perfect squares.
 Subtraction problem.
 (
+ )(
)
Examples:
 x2 – 25
2x2y + 10xy3
9x2 – 100
16x2 – 36y2
3. Perfect Square Trinomials
 Three terms.
 1st and last terms are perfect squares.
 Check your answer – multiply together and double it.
 (
)2
Examples:
 x2 + 16x + 64
3x2 – 30x + 75
16x2 + 56x + 49
4. Factoring x2 + bx + c
 What multiplies up to the last number and adds up to the second number.
 (x
)(x
)
Examples:
 2x2 + 18x + 40
x2 – 9x + 18
x2 + 5x – 14
Perfect
Squares
----------1 = 12
4 = 22
9 = 32
16 = 42
25 = 52
36 = 62
49 = 72
64 = 82
81 = 92
100 = 102
121 = 112
144 = 122
169 = 132
5. Factoring ax2 + bx + c
 Multiply the first and last number.
 What multiplies up to that number and adds up to the second number.



a
a
and
2nd #
1st #
Put in lowest terms
(
)(
)
Examples:
 2x2 – 7x – 4
5x2 – 11x + 2
2x2 + 4x + 2
Practice:. First tell what step you will use and then factor.
1.
4.
x2 – 10x + 21
4x2 – 1
step _______
step _______
2.
5.
12x3 + 4x2 + 8x
step ________
25x2 + 20x + 4
step _________
3.
3x2 + 11x – 4
step _______