SOLUTION: What is the third term of (x + y)^9?

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Question 781563: What is the third term of (x + y)^9?
Answer by fcabanski(1391) About Me  (Show Source):
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Use Pascal's triangle and the following formula to expand binomials (x+y)^n.


nC0 * x^n * y^0 + nC1 * x^(n-1) * y^1 +...nCn * x^(n-n) * y^n where n is the row (starting from 0) of Pascal's triangle, the number after C is the item position in that row, starting from 0.


For the third term of (x+y)^9 it's 9C2 x^(n-2) + y^2


The number in Pascal's triangle that is the 9th row (counting the first row as 0), number in position 2, starting from 0, is 36.


36x%5E7y%5E2