What are the explicit equation and domain for an arithmetic sequence with a first term of 5 and a second term of 2?
an = 5 − 2(n − 1); all integers where n ≥ 1
an = 5 − 2(n − 1); all integers where n ≥ 0
an = 5 − 3(n − 1); all integers where n ≥ 1
an = 5 − 3(n − 1); all integers where n ≥ 0

The easiest way to answer this is to try all choices, plug in values for the 1st term and 2nd term then check if the answer matches with 5 and 2. (n = 1 and n = 2)

We know that n starts with 1 because that is our 1st term, we do not have 0th term, therefore that leaves us with 2 choices.

Choice 1: an = 5 − 2(n − 1); all integers where n ≥ 1

n = 1

a1 = 5 – 2 (1 – 1) = 5 – 2 (0)

a1 = 5

n = 2

a2 = 5 – 2 (2 – 1) = 5 – 2 (1)

a2 = 3   (FALSE!)

Choice 2: an = 5 − 3(n − 1); all integers where n ≥ 1

n = 1

a1 = 5 – 3 (1 – 1) = 5 – 3 (0)

a1 = 5

n = 2

a2 = 5 – 3 (2 – 1) = 5 – 3 (1)

a2 = 2   (TRUE)

Therefore the correct answer is:

an = 5 − 3(n − 1); all integers where n ≥ 1

127

whether it's diameter, or radius, i believe if i remember correctly from school, every amount has to always add up to 180. so if you take 53, and starting adding, long story short, taking 127 and adding it to 53, gives you 180.