Question

expand this
a + b whole cube
a - b whole cube

Answer 1

$( {a + b})^{3} = { \alpha }^{3} + {b}^{3} + 3ab(a + b) \\ ( {a - b}^{3} ) = {a}^{3} - {b}^{3} - 3ab(a - b) \\ |hope \: itwill \: help \: you|$

thank you

Answer 2

$\underline{\underline{\huge\mathfrak{your\:answer}}}$

1. (a+b)^3

= (a+b)(a+b)^2

on expansion, we get

= (a+b)(a^2 + 2ab + b^2)

= a^3 + 2a^2b + ab^2 + a^2b + 2ab^2 + b^3

= a^3 + 3a^2b + 3ab^2 + b^3

similarly,

2. (a-b)^3

= (a-b)(a-b)^2

on expansion, we get

= (a-b)(a^2-2ab+b^2)

= a^3 - 2a^2b + ab^2 - a^2b + 2ab^2 -b^3

=a^3 -3a^2b + 3ab^2 - b^3