Formula of (a+b)^3

Question

Give the algebraic formula

Answer 1

Take it from me, THIS SHOULD BE MEMORIZED: = a³ + 3a²b + 3ab² + b³

 

note carefully the coefficients of the four terms (1, 3, 3, 1) and the pattern of exponents.

Answer 2

Edited solution; typos corrected.

 

Are you familiar with using Pascal's triangle to expand this?

 

1

1 1

1 2 1

1 3 3 1

 

(a + b)³ = a³ + 3a²b + 3ab² + b³

 

Or you can do it the long way, by expanding (a + b)(a + b)(a + b).