Question

can someone please explain how to do this ...please explain in steps

Find the sum of the first 26 terms of the following sequence:

-12, -13, -14 . . .
-1274 -637
-98 -312

Answer 1

You can use an arithmetic sequence formula to find the sum.

First term is -12, common difference is -1, number of terms is 26.

Answer 2

s(n)=n/2 (2a+(n-1)d)
n=no of terms.=26
a=first term=-12
d=common difference=-13-(-12)=-1
plug in all the values
26/2(-24+(26-1)(-1))
=13(-49)=-637

Answer 3

thank you sooo much :)

Answer 4

its ok .. ur welcome.!! :)

Answer 5

lol. You could let her at least try to do some of the work...

Answer 6

thank you both