Question

plss answer...its fast....​

Answer 1

❤(a−b)3=a3−3a2b+3ab3−b3✔

❤(a+b)3 =a3+3∗a2∗b+3∗a∗b2+b3✔

^_^.

Answer 2

Answer:

( a + b )³ = a³ + b³ + 3a²b + 3ab²  and

( a - b )³  = a³ - b³ - 3a²b + 3ab²

Step-by-step explanation:

Given: ( a + b )³ and ( a - b )³

To find: Expansion of Given expressions

First consider,

( a + b )³

= ( a + b ) × ( a + b )²

=  ( a + b ) × ( a² + b² + 2ab )    ( identity used, ( a + b )² = a² + b² + 2ab  )

= a × ( a² + b² + 2ab )  + b × ( a² + b² + 2ab )

= a³ + ab² + 2a²b + a²b + b³ + 2ab²

= a³ + b³ + 2a²b + a²b + ab² + 2ab²

= a³ + b³ + 3a²b + 3ab²

Now Consider,

( a - b )³

= ( a - b ) × ( a - b )²

=  ( a + b ) × ( a² + b² - 2ab )      ( identity used, ( a - b )² = a² + b² - 2ab  )

= a × ( a² + b² - 2ab )  - b × ( a² + b² - 2ab )

= a³ + ab² - 2a²b - a²b - b³ + 2ab²

= a³ - b³ - 2a²b - a²b + ab² + 2ab²

= a³ - b³ - 3a²b + 3ab²

Therefore, ( a + b )³ = a³ + b³ + 3a²b + 3ab²  and

                  ( a - b )³  = a³ - b³ - 3a²b + 3ab²