Algebra II

Question

Prove that (x+y)³=x³+3x²y+3xy²+y³ is an identity.

 

 

 

 

 

Use the identity to simplify (2a-3)³

Answer 1

Here are two ways to achieve your goal.

 

One is to square (x+y) and then multiply that result by (x+y).

 

The other is to use the Binomial Theorem (including Pascal's triangle)--if you know it.