Question

What are the first three terms of the sequence defined by the following equation?

an = 6+(n- 1)(-4).

Answer 1

A

Explanation:

First term = 6 + (1 -1)(-4) = 6 + 0 = 6.

2nd term = 6 + (2 - 1)(-4) = 6 + (-4) = 2.

a3 = 6 + (3 - 1)(-4) = 6 + (-8) = -2.

Its Choice A.

Answer 2

`a_n=6+(n-1)(-4)=6+(n)(-4)+(-1)(-4)=6-4n+4=10-4n`

Put n = 1, n = 2 and n = 3 to the equation:

`a_1=10-4(1)=10-4=6\\\\a_2=10-4(2)=10-8=2\\\\a_3=10-4(3)=10-12=-2`

Answer: A. 6, 2, -2.