Question

Find the 72nd term of the arithmetic sequence 11, 7, 3, ...

Answer 1

-273

Explanation:

find the common difference:

d = 7 - 11 = - 4

a_1 = 11

a_72 = (72 - 1)* (-4) + a_1

a_72 = (71)* (-4) + 11

a_72 = -273