Question

factorise using identities

Answer 1

Take b common then use a2-b2 formula
b(16a2-64b2)
b(4a+8b)(4a-8b)

Answer 2

16a^2b-64b^3
16a^2b-64b^2×b
b(16a^2-64b^2)
b{(4a-8b)(4a plus 8b)
[using identity - a^2-b^2]