Question

factor if possible:
y^6-216

Answer 1

y^6-216 =[ (y^2)^3 - 6^3)]
= (y^2 - 6)((y^2)^2 - 6y^2 + 6^2)
= (y^2 - 6)(y^4 - 6y^2 + 36)

Answer 2

i used the identity
a^3 - b^3 = (a-b)(a^2 - ab + b^2)