Question

Find Sn for the given arithmetic series.

a1=18, d=-10, n=12

Answer 1

The formula to calculate sum for AP is
\(\huge S_n=n/2(2a_1+(n-1)d)\)
now just plug in the values, u will find the sum....

Answer 2

@kristina95 did u try plugging values in that formula?
do u need further help ?

Answer 3

so would it be -444? or am I doing something wrong

Answer 4

thats correct! its -444.
thats your sum :)