4a2+b2+4ab+8a+4b+4=?
(a) (2a+b+2)2
(b) (2a−b+2)2
(c) (a+2b+2)2
(d) None of these
4a2+b2+4ab+8a+4b+4=4a2+b2+4+4ab+4b+8a=2a2+b2+22+2×2a×b+2×b×2+2×2a×2=(2a+b+2)2
Factorise 2a7−128a