1. Factoring Sums & Differences of Cubes

2. Factoring Sums & Differences of Cubes
Sum & Difference of Cubes:
Has two terms
The terms are separated by a + or – sign
Each term is a perfect cube

3. Factoring Sums & Differences of Cubes
Factors of a Sum/Difference of Cubes:
a3 + b3 = (a + b)(a2 – ab + b2)
a3 – b3 = (a – b)(a2 + ab + b2)
Sum of Cubes
Difference of Cubes

4. Factoring Sums & Differences of Cubes
Example 1: Factor each of the following
polynomials completely.
s3 + t3 = (s + t)(s2 - st + t2)
v3 – w3 = (v – w)(v2 + vw + w2)

5. Factoring Sums & Differences of Cubes
Example 2: Factor each of the following
polynomials completely.
8x3 – 27
= (2x – 3)((2x)2 + (2x)(3) + (3)2)  Use the pattern
a3 – b3 = (a – b)(a2 + ab + b2)
= (2x – 3)(4x2 + 6x + 9)
b) 9x4 – 9x
= 9x(x3 – 1)  First remove the GCF
= 9x(x – 1)(x2 + x + 1)  Factor the difference of cubes x3 – 1

6. Homework
Do #1 – 19  odd questions only on page 120 section 4.2 for Thursday 