Question

What is the first term in the sequence for which d = -2 and a7 = 3?

a.
-6

b.
12

c.
15

d.
-12


Please select the best answer from the choices provided

a) A
b) B
c) C
d) D

Answer 1

c.

15

Explanation:

Answer 2

Final answer is c. 15

Explanation:

We need to find about what is the first term in the sequence for which d = -2 and a7 = 3

We will use nth term formula of arithmetic sequence.

`a_n=a+\left(n-1\right)d`

we have been given a7 that means 7th term is 3

so plug n=7, d=-2 and a_n=3 into above formula

`3=a+\left(7-1\right)(-2)`

`3=a+6(-2)`

`3=a-12`

`15=a`

Hence final answer is c. 15