1. Factoring Special Cases
ALGEBRA 1 LESSON 9-7
Factor 5x2 – 80.
5x2 – 80 = 5(x2 – 16) Factor out the GCF of 5.
= 5(x + 4)(x – 4) Factor (x2 – 16).
Check: Use FOIL to multiply the binomials. Then multiply by the GCF.
5(x + 4)(x – 4)
5(x2 – 16)
5x2 – 80
5-11

2. Factoring Special Cases
ALGEBRA 1 LESSON 9-7
Factor each expression.
1. y2 – 18y a2 – 24a + 16
3. p2 – x2 – 225
5. 5m2 – c2 + 20c + 50
(y – 9)2
(3a – 4)2
(p + 13)(p – 13)
(6x + 15)(6x – 15)
5(m + 3)(m – 3)
2(c + 5)2
5-11