SOLUTION: What is the coefficient of x^-5 in the expansion of (x^3 - 1/x^2)^10?

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Question 1040820: What is the coefficient of x^-5 in the expansion of (x^3 - 1/x^2)^10?
Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
The binomial expansion formula as applied in this case is as follows:

= sum%28%28-1%29%5Ek%2A%28matrix%282%2C1%2C10%2Ck%29%29%2Ax%5E%2830-5k%29%2Ck=0%2C+10%29
==> 30-5k = -5 ==> -5k = -35 ==> k = 7.
Hence the coefficient of x%5E%28-5%29 is %28-1%29%5E7%2A%28matrix%282%2C1%2C10%2C7%29%29+=+-120.