Question 474907
Use the formula for the nth term of an arithmetic series:

{{{a[n] = a[1] +(n-1)d}}}

==> 8000 = -8000 + (n-1)4 ==> 16000 = 4(n-1)

==> n-1 = 4000 ==> n = 4,001, the number of integers from -8,000 to 8, 000 divisible by 4.
(Note that we have let -8,000 be the first term of the arithmetic series, which is actually divisible by 4.)