Answer:
Final answer is c. 15
Step-by-step 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.
we have been given a7 that means 7th term is 3
so plug n=7, d=-2 and a_n=3 into above formula
Hence final answer is c. 15