Question

The simple formula for the nth term of an arithmetic sequence is an = 6n + 14. What is the explicit formula corresponding to the simple formula?

A. an = 20 + (n - 1)(6)
B. an = 14 + (n - 1)(6)
C. an = 14 + 6n
D. an = 20 + (n)(6)
E. an = 6 + (n - 1)(14)

Answer 1

put n=1 to find first term
\[n=1 \rightarrow a_n=a_1=6(1)+14=20\\a_n=a_1+(n-1)d\]

now find d
\[d=a_2-a_1\\a_2=2(6)+14=26\\a_1=20\\a_2-a_1=d=26-20=6\]

Answer 2

can you go on ?

Answer 3

its e

Answer 4

\[a_n=a_1+(n-1)d \]

Answer 5

try again !

Answer 6

its not a or b

Answer 7

so its d

Answer 8

a1=20
d=6
now an =?
write it by yourself
do not see choices

Answer 9

\[a_n=a_1+(n-1)d=\\a_n=20+(n-1)6\]