1. ## cubes

hi can someone show me the formula for these please-

$(a - b)^3$

and

$(a + b)^3$

thanks

2. Hi,

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

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

3. hi
for the second one u can use :
$(a+b)^n=\sum_{k=0}^{n}\begin{pmatrix}
n\\
k
\end{pmatrix}a^{n-k}b^{k}$

( Binomial theorem )

4. could anyone also tell me the formula for:

$(a + b)^4$

and

$(a - b)^4$?

thankyou

5. Originally Posted by mark
could anyone also tell me the formula for:

$(a + b)^4$

and

$(a - b)^4$?

thankyou
The Binomial Theorem: Formulas