Subject :IMO Class : Class 8
(0.2u2 - 0.9v)(0.2u2 + 0.9v) =
(a) 0.04u4 + 0.81v2
(b) 0.04u4 - 0.36u2v - 0.81v2
(c) 0.04u2 - 0.81v2
(d) 0.04u4 + 0.36u2v + 0.81v2
Pls tell me what is the answer and also why