Expand #(a+2b)^3# using the binomial theorum with steps?

1 Answer
Robert W.
Aug 7, 2018

#a^3 + 6a^2b+12ab^2+8b^3#

Explanation:

From Pascal's triangle (or factorial notation), the coefficients are:

1, 3, 3, 1

i.e. 1 for #a^3#, 3 for #a^2# and so on.

You then multiply the first time by #(2b)^0#, second term by #(2b)^1#, third term by #(2b)^2# and the final term is #(2b)^3#. I like to think of it as a pattern for these simple ones. There are some complicated formulae you can apply to every single expansion if you wish to research this further.

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