shortcut for exponential problem  TOPIC_SOLVED

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shortcut for exponential problem

Postby latinlioness08 on Mon Apr 11, 2011 1:57 am

The coefficient in front of the x^5 term in (x+2)^7 is:
a. 21
b. 7
c. 42
d. 84

I know the answer is d. However, to aquire this answer I had to literally FOIL the entire thing. I took it to (x^4+ 8x^3+24x^2+32x+16)(x^3+6x^2+12x+8) before i knew how to tell what the answer was. Is there some shortcut to know what the coefficient in front of the x^n term is in a basic expression like this?
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  TOPIC_SOLVED

Postby stapel_eliz on Mon Apr 11, 2011 12:05 pm

latinlioness08 wrote:Is there some shortcut to know what the coefficient in front of the x^n term is in a basic expression like this?

Yes, there is a shortcut. It's called "the Binomial Theorem". :wink:
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Re: shortcut for exponential problem

Postby latinlioness08 on Mon Apr 11, 2011 10:30 pm

Got it:) Thanks!
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