Question

please solve this question

Answer 1

( a + b )³ - ( a - b )³ = 2b³ + 6a²b or 2b(3a² + b²)

and -6b(a+b)(a-b)

now we get

2b(b^2+3a^3)-6b(a^2-b^2)

now after solving get the answer ...

Answer 2

(a+b)^3 -(a-b)^3 -6b(a^2 -b^2)

=a^3 +b^3 + 3(a+b)ab -(a^3-b^3-3ab(a-b)) -6b(a+b)(a-b)

=a^3+b^3+3ab(a+b) -a^3 +b^3 +3ab(a-b)-6b(a+b)(a-b)

=3ab(a+b) +b^3 +3ab(a-b)-6b(a-b)(a+b)

=3ab(a+b+a-b) +b^3 -6b(a-b)(a+b)

=6ab(a)+b^3 -6b(a-b)(a+b)

=6b(a^2-a^2+b^2)+b^3

=6b(b^2) +b^3

=7b^3