Question 927997: When (2a + b)^8 is expanded, what is the coefficient of the term a^3 b^5
Hint: Remember the 2.
Answer by jim_thompson5910(35256)   (Show Source):
You can put this solution on YOUR website! For (x+y)^n, each term is of the form (n C k)*(x)^k*(y)^(n-k)
We want the term where the exponent on x is 3, so k = 3. The value of n is n = 8. Also, x = 2a and y = b
So,
(n C k)*(x)^k*(y)^(n-k)
(8 C 3)*(2a)^3*(b)^(8-3)
56*(8a^3)*(b^5)
488a^3b^5
So we can see that the coefficient here is 488
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