(2a-b)^2*(4a^2+b^2)^2*(2a+b)^2={[(2a-b)(2a+b)]*(4a^2+b^2)}^2=[(4a^2-b^2)(4a^2+b^2)]^2=(16a^4-b^4)^2=256a^8-32a^4b^4+b^8