Question

Check my answer please :)

Identify the 31st term of an arithmetic sequence where a1 = 26 and a22 = -226.

-334
-274
-284
--> -346 my answer

Answer 1

ok...
we have common difference as (-226 - 26)/21 = -12
and the first term is
26
so..
tn = a + (n-1)d
t31 = 26 + (30)(-12)
= -334
so... u need to recheck ur answer :)

Answer 2

ohh, okay but why is a1 negative?

Answer 3

huh... between a1 and a22 the common difference is repeated 21 times...

so if u subtract
a1 from a22 and divide it by 21 .. u get the common difference :)

Answer 4

okay thank you :)

Answer 5

u r welcome