Question

Find an equation for the nth term of the arithmetic sequence.

-20, -16, -12, -8, .

Answer 1

1) a30=96

2) 30(-20+96)/2

3) 1140

Answer 2

we are given with the sequence -20, -16, -12, -8. From this sequence, we can see that the arithmetic difference is +4, from -(-20 + 16). hence following the arithmetic formula of an = a1 + d *(n-1). Substituting, an = -20 + 4 *(n-1) where n is an integer