Question

I need to factor b^3 - 8a^3. How would I start?

Answer 1

notice how 8a^3 = (2a)^3

Answer 2

so

b^3 - 8a^3

is the same as

b^3 - (2a)^3

from here you use the difference of cubes factoring rule to factor

Answer 3

that rule is

x^3 - y^3 = (x-y)(x^2+xy+y^2)