In the expansion of \((ab+bc+ca)^{12}\) find the coefficient of \({a}^{9}{b}^{11}c^{4}\)
Hey, forgive me for asking but are you a K12 student?
wdym?
I'm asking because I am, and I've seen this problem or a binomial theorem problem similar to this before since Im in Honors Alg 2 :) So I'm just wondering if you are.
Oh I'm in fifth grade so lol
Oh ok lol
We can write this as
[ b(a + c) + ca ] 12
We have .....
C( 12, 1) * [ b ( a + c)]11 * (ca)1 =
(12)b11 * (a + c)11 * a1 c1 =
(12)acb11 * (a + c)11 =
(12)acb11 * C(11,3) (a)8 * c3 =
(12) acb11 * (165)a8 c3 =
1980 a9 b11 c4
