Question

For the 12th term of the arithmetic sequence whose common difference is d=7 and whose first term is (in the picture)

Answer 1

SInce we know the first term and the common difference of the sequence, we can write the nth term formula of the sequence.

Nth term formula of an arithmetic sequence:

$a_n=a_1+(n-1)d$

In this case:

a1 = -10

d = 7

Thus:

$a_n=-10+(n-1)7$

Since we want to find the 12th term, we substitute n = 12 in the formula:

$a_{12}=-10+(12-1)7=-10+11\cdot7=-10+77=67$Thus, the 12th term of the sequence is 67.