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Expert: Sherry Wallin - 11/14/2010


Question
I am having difficulty with this problem. (2x-5y)^6

Answer

binomial expansion
Jillian~

There are a couple of ways to expand this and several different methods. I am not sure which ones you have seen but you could rewrite
(2x-5y)^6 as (2x-5y)^2*(2x-5y)^2*(2x-5y)^2 and then expand one of them as 4x^2 -20xy + 25y^2 and now you have 3 factors with this expansion. Then you would multiply two of those factors and get a result and take that result and multiply it by the third factor of 4x^2 -20xy + 25y^2.
I prefer what I call the'grid' method to multiply trinomials.

Attached is the grid method and an explanation.

Please let me know if you have any other questions or need this explained further.

Math Prof

Sherry Wallin

Expertise

I can answer most questions up through Calculus and some in Number Theory and Abstract Algebra.

Experience

I have had my Bachelor's Degree since 1987 and have been a teacher since 1988. I earned my Masters Degree in Mathematics May 2010. I have been teaching at the same community college since 2002.

Education/Credentials
I have taught 12 years at the community college level, medical college, and technical college as well as a high school instructor and alternative education instructor and charter school instructor.

Awards and Honors
Master's GPA 3.56 Bachelor's GPA 3.34 Post grad work not degree related GPA 4.0

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