the third term is an arithmetic sequence is 10 and the fifth term is 26. if the first term is a1, which is an equation for the nth time of this sequence?

I don't i'm asking you to pick one, I projected the question exactly the way it was written help me out please.

Apr 11th, 2015

please I need help, please. you seem nice please help a stupid person who knows nothing of math to understand and finally learn how to past her math regents it's the second time i'm about to take it and this is just a practice and all I see is black and white.

In the last concept we were given the common difference directly or two consecutive terms from which we could determine the common difference. In this concept we will find the common difference and write term rule given any two terms in the sequence.

Example A

Find the common difference, first term and term rule for the arithmetic sequence in which 3rd term= 10 and the 5th term=26

Solution: We will start by using the term rule for an arithmetic sequence to create two equations in two variables:

a3=10 so a1+ (3-1)d=10 or more simply: a1+2d=10

a5=26 , so a1+(5-1)d=26 or more simply: a1+4d+26

Solve the resulting system:

When a1+2d=10 is subtrated from a1+4d+26 we find d=8