Question

3. What is the 41st term of the arithmetic sequence where a1 = 15 and a15 = -41 ? help me! Im lost

Answer 1

here first term is 15?

Answer 2

yep, thats why I got messed up in the first place, it doesn't make sense

Answer 3

a15= -41
a+14d = -41
15+14d = -41
14d= -56
d= -4
now, a= 15 and d= -4
a41 = a+40d
= 15-40*4
= -145 Answer

Answer 4

ok that makes sense now, but where did the "d" come from?

Answer 5

15th term of series is given and 1st term is also given, so apply
a15= a+14d
put the value of a i.e. 1st term you will get eqn. in d only i.e. commen difference.

Answer 6

Ohhhh, ok well thanks!