Question

How do you write a rule for the nth term of the arithmetic sequence and then find `a_10` for `-25, -29, -33, -37, -41`?

Answer 1

nth term = `-4n-21`
10th term = -61

Explanation:

nth term = `a+(n-1)d`
where a = first term of the sequence and d is the constant added or subtracted between successive terms

Here we will substitute a with -25 and d with -4
nth term = `-25+(n-1)-4`
= `-25+(-4n+4)`
= `-25-4n+4`
= `-4n-21`
10th term = `-4(10)-21`
= `-40-21`
= `-61`