Question

What is the second term in the expansion of (2x + 7)^6 ?

Answer 1

A. 1344x^4
B. 1344x^5
C. 23,520x^4
D. 23,520x^5

Answer 2

lol i think i must be doing the same course as u cause this is everything im going lol

Answer 3

\[\Large(a+b)^n = \sum_{k=0}^n\left(\begin{matrix}n \\ k\end{matrix}\right)x^{n-k}y^k\]Second term is when k = 1 so \(\left(\begin{matrix}6 \\ 1\end{matrix}\right)(2x)^{6-1}7^1 = 6\cdot2^5\cdot 7x^5 = \boxed{1344x^5}\)

Answer 4

http://www.wolframalpha.com/input/?t=crmtb01&f=ob&i=(2x%20%2B%207)%5E6

Answer 5

Thanks!!

Answer 6

You're welcome.