00:01
Okay, so we can look at this one.
00:03
We're finding the coefficient a of the given term in each of these expansions of their given polynomials.
00:09
So when we do this, we use our final theorem in there.
00:12
If we look at a plus b to the n power, then we're going to say that is the sum of all these where this is the combination, take the combination of n choose k.
00:22
And then a is going to be represented like the base a is going to be raised the exponent of n minus k.
00:28
So when we start, we're going to take the n minus 0 is just n, and then b to the k power.
00:34
So in this first case here, we want to look at x plus three to the 12 power, and we want to find when we have x to the fifth as my term.
00:45
And the y values here is three, so that means, or the b value is three, so it's just going to kind of be part of the coefficient now.
00:52
So in order to do that, since it's 12 here, n is going to be 12, to get a value of five.
00:58
Here, k has to be 7.
01:00
It's 12 minus 7 gives me my 5...