Help!
Find the 7th term of the expansion of (3c + 2d)^9

Question

Help!
Find the 7th term of the expansion of (3c + 2d)^9

dan815 · Answer

ok

dan815 · Answer

u know pascals triangle

dan815 · Answer

pascal was a very smart guy

anonymous · Answer

Yeah

anonymous · Answer

Can you please tell me how to do this problem??

campbell_st · Answer

well its the same process as the lats question you posted... 

there will be 10 terms so r starts at 0

the general term is 

$$^nC_{r} = (a)^{n - r}(b)^r$$

in your question you have n = 9, r = 6, a = 3c and b = 2d

just substitute and evaluate...

anonymous · Answer

The answer I got was not one of the choices

campbell_st · Answer

really did you evaluate the combination...?

campbell_st · Answer

here is a combinations calculator that may help you http://www.mathsisfun.com/combinatorics/combinations-permutations-calculator.html...

anonymous · Answer

Yeah I evaluated the combination and got 84

Here are the answer choices
a.760c^3d^6
b.760c^4d^5
c.145,152c^3d^6
d.145,152c^4d^5

anonymous · Answer

When I click on the link it says that the file can not be found

campbell_st · Answer

ok... well good luck... you could always just google combinations calculator

anonymous · Answer

So you arnt going to help me???

campbell_st · Answer

well I have... helped you...

dan815 · Answer

u see pascal was a genius

dan815 · Answer

how did he draw that triangle and know all those numbers were combinations when u added the numbers above those numbers in triangle

campbell_st · Answer

and unfortunately Pascal has done his best work by the age of 22, became a priest and a drunk... sad story

dan815 · Answer

=[

campbell_st · Answer

he also did a huge amount of work in descriptive drawing...

dan815 · Answer

he saw that the pacal triangle flipped looked like a martini, so he found his calling