a^(2+6) - a^2b^6 a2+6−a2b6
= a^2a^6-a^2b^6=a2a6−a2b6
=a^2(a^6-b^6)=a2(a6−b6), here color(red)(a^2)a2 is common between the terms
=a^2(a^(3xx2)-b^(3xx2))=a2(a3×2−b3×2)
=a^2[(a^3)^2-(b^3)^2]=a2[(a3)2−(b3)2]
color(red)("This is of the form " x^2-y^2 = (x-y)(x+y), "where " x=a^3 " and " y = b^3)This is of the form x2−y2=(x−y)(x+y),where x=a3 and y=b3
=a^2(a^3-b^3)(a^3+b^3)=a2(a3−b3)(a3+b3)
Now we factorize (a^3-b^3)(a3−b3) and (a^3+b^3)(a3+b3):
color(red)("We know that " (a^3-b^3)=(a-b)(a^2+ab+b^2)We know that (a3−b3)=(a−b)(a2+ab+b2)
color(red)("And "(a^3+b^3)=(a+b)(a^2-ab+b^2)And (a3+b3)=(a+b)(a2−ab+b2)
Then,
a^2(a^3-b^3)(a^3+b^3)=color(blue)(a^2(a-b)(a^2+ab+b^2)(a+b)(a^2-ab+b^2)a2(a3−b3)(a3+b3)=a2(a−b)(a2+ab+b2)(a+b)(a2−ab+b2)