Answer:
4a^4b^2 - 1
Step-by-step explanation:
(-1 - 2a^2b)(1 - 2a^2b) =
= -(1 + 2a^2b)(1 - 2a^2b)
= -(1 - 4a^4b^2)
= -1 + 4a^4b^2
= 4a^4b^2 - 1
