Question

please help/explain expanding binomials
(a+b)^4
(2x-y)^8
(x+2y)^9

Answer 1

To expand, you multiply the numbers inside the [parenthesis] , by the exponent on the outside.
For example: the first one, you multiply the a and 4 to get 4a, and the b with the 4 to get 4b, so the expanded form of the first binomial is:
4a + 4b

Answer 2

n = no. of terms
r= 0 for the first term and so on
a = term one of the binomial and
b = term 2 of the binomial

Answer 3

use Pascal's triangle

Answer 4

4th power is 4th row

Answer 5

http://images.tutorvista.com/cms/images/67/1.png

pay close attention to the exponent there for "x" and "y" for the BINOMIAL THEOREM

notice that, "x" exponent from term to term, left to right, is decreasing
it begins with HIGHEST which is the binomial's exponent, down 1 and so on
so if (x+y)^10, x will start as \(\color{red}{x^{10}}\), then on next term to \(\color{red}{x^9}\) and \(\color{red}{x^8}\) and \(\color{red}{x^7}\) and \(\color{red}{x^6}\) and