Concept: 1 Mark
Application: 3 Marks
We have,
x4a+x2ay2b+y4b=(x2a)2+x2ay2b+(y2b)2
=(x2a)2+2x2ay2b+(y2b)2−x2ay2b
=(x2a+y2b)2−(xayb)2
=(x2a+y2b+xayb)(x2a+y2b−xayb)
=(x2a+xaya+y2b)(x2a−xayb+y2b)
∴x4a+x2ay2b+y4bx2a+xayb+y2b
=(x2a+xayb+y2b)(x2a−xayb+y2b)(x2a+xayb+y2b)
=x2a−xayb+y2b