Find the 21st term of the arithmetic sequence 8,12,16,20

Answer 1

Since the pattern is based upon adding to 4 to each additional term, you solve this problems this way:

8 12 16 20 24 28 32 36 40 44

48 52 56 60 64 68 72 76 80 84 88!

Answer 2

Larissa:

The formula for the nth term of an arithmetic sequence is the following:

a(n) = a₁ + (n-1) *d where d is the common difference, a₁ is the first term, and n is the sequence term.

In this case, d = 4, a₁ = 8. Can you figure what n is ? Once you have n you can plug into the formula.