Question

Find the sum of the arithmetic sequence 5, -2, -9, -16..., -44

Answer 1

-136.5

Sn=A1+An/2*n

Step-by-step explanati

d=-2-5=-7

A1=5 An=-44 n=-49/7=7

S7=5+(-44)/2*7=19.5*7=-136.5