00:01
So the deal with this problem is to expand this binomial x minus 2 rays to the 5th.
00:06
It's best to turn this into an addition problem so you can apply pascal's triangle.
00:11
I thought pascal's triangle would be easier here because the fifth row has kind of iconic digits, 151010, 5 .1.
00:20
So that's easy to remember and keep in mind.
00:25
So continuing onward with this expansion, we can just plug in these terms for a and b.
00:34
So let me get that out.
00:37
So the first term is 1 times x2 .5th.
00:41
And we don't include the b term because it's technically being raised to the zeros.
00:47
Then we get 5 times x2 .4th minus 2 to the first because it's being reintroduced.
01:00
Then we get 10 times x2 3rd times minus 2 to the second because that b term is going to be counting up as we go along.
01:15
Then we add again 10 x to x squared times minus 2 to be third...