If the x variant of 24 was 8 how to I solve?

Find the sum of the first 8 terms of the following sequence. round to the nearest hundredth if necessary.

Kilgore trout creates a new scale to diagnose depression. however, his scale only assesses one symptom of depression while ignoring others. which of the following is his new scale most likely lacking? a) test-retest reliability b) discriminant validity c) criterion validity d) alternate-forms reliability e) content validity f) none of the above

Which is the value of this expression when p=3 and q=-9