Answer: -250000
Step-by-step explanation:
Sum of arithmetic terms = n/2[2a + (n - 1)d],
where 'a' is the first term,
'd' is the common difference between two numbers,
and 'n' is the number of terms.
'a' = -1
'd' = -2
'n' = 500
plug and chug
(500)/2[2(-1) + ((500)-1)*(-2)] =
250[-2 + -998] =
250[-1000] =
-250000
