Finding the common difference or ratio when given only two terms
For Arithmetic Sequences
Subtract the terms
Divide by the difference in the indices
(make sure you subtract in the right order)
For Geometric Sequences
Divide the terms
Root by the difference in the indices
N) Find the common difference of an arithmetic sequence with 𝑎1=−4 and 𝑎5=16
O) Find the common ratio of a geometric sequence with 𝑔2=56 and 𝑔5=7