each sequence is an arithmetic sequence. write a formula for tn, then use it to determine the indicated term?

Question

1,5,9,13...... t17

Answer 1

to determine the nth term, you use the formula,

nth term = 1st term + (n-1)(difference)

Answer 2

1 + 4 (x-1)
1 is the starting term, and 4 is the increment value. Alternatively, this works also, which looks a bit better.
4x - 3

Using this, input 17 for x, which gives 4 * 17 - 3, which is 65

Answer 3

an=a1+(n-1)d

d=5-1=9-5=13-9=4

The last term
117=1+(n-1)4
116 =4(n-1)
n=30 terms