In the arithmetic sequence -7, -4, -1, 2, ... , what term is 44 ?

Sagot :

We have -7 as the 1st term, we have 3 as the common difference so:
[tex]n= \frac{a_n-a_1}{d} +1= \frac{44+7}{3} +1 =\frac{51}{3} +1=18[/tex]
The formula for the arithmetic sequence is:
[tex]a_n=a_1+d(n-1)[/tex]

To find the common difference:
-7, -4
The common difference is 3, so:

To find what term is 44:
[tex]44=-7+(n-1)3[/tex]
Add 7 to both sides
51=3(n-1)
Distribute
51=3n-3
Add both sides by 3
3n=54
Divide both sides by 3
n=18

Therefore, 44 is the 18th term. Hope this helps =)