What are (a+b)^3 and (a-b)^3 equal to?

Question

they are identities

Answer 1

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

or

a^3 + b^3 + 3 a^2 b + 3 a b^2


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

Or

a^3 - b^3 - 3 a^2 b + 3 a b^2

Answer 2

Remember that (a+b)^3 = (a+b)(a+b)(a+b)

You can foil out the first two binomials and get:

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


Distributing the binomial over the trinomial again gets you your answer:

(a^3+3a^2b+3ab^2+b^3)


Similarly, (a-b)^3 = (a^3-3a^2b+3ab^2-b^3)

Answer 3

Using the binomial theorem,

(a+b)³ = a³ + 3a²b + 3ab² + b³

(a-b)³ = a³ - 3a²b + 3ab² - b³

I'm not sure what you mean when you say they are identities. Are a and b supposed to represent something?

Answer 4

(a+b)^3 = a^3 +3a^b+3ab^2 + b^3
(a-b)^3 = a^3 - 3a^2b +3ab^2 -b^3
You should commit these expansions to memory. It will save you a lot of time if you do.

Answer 5

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

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

Answer 6

cheating isnt good figure it out yourself instead of making other people do the work for you bad bad bad........