The Total solution for NCERT class 6-12
x4 + x2y2 + y4 = (x2)2 + 2x2y2 + y4 –x2y2 (Adding andsubtracting x2y2)= (x2 + y2)2 – (xy)2 {∵ a2 – b2 =(a + b) (a – b)}= (x2 + y2 + xy) (x2 + y2 –xy)= (x2 + xy + y2) (x2 – xy + y2)