Question

Please help! Find the fifth term of the expression (2x+1)^7

Answer 1

Are you writing the polynomial in descending degree order?

Answer 2

they are probably looking for the 3rd power in the expansion

Answer 3

The options:
a. 280x^3
b. 84x^2
c. 140x^2
d. 168x^3

Answer 4

\[
(2 x+1)^7=128 x^7+448 x^6+672
x^5+560 x^4+280 x^3+84 x^2+14
x+1
\]

Answer 5

Did you get it?

Answer 6

Yea, thanks for the explanation!

Answer 7

\[
{7 \choose 3} 2^3 x^3 = 280 x^3
\]

Answer 8

yw