Question
Factorise each of the following:
a4 - 16b4
Solution
a4 - 16b4
a4 - 16b4 = (a2)2 - (4b2)2 = (a2 - 4b2)(a2 + 4b2)
| Using Identity III
= {(a)2 - (2b)2}(a2 + 4b2)
= (a + 2b)(a - 2b)(a2 + 4b2)
| Using Identity III
