Question

NEED HELP!!!!!!!!!!!!!!!!!!!!!

Answer 1

Answer:-602

Explanation:

First term=a=-143

common difference=d=-134-(-143)=9

Using the formula

Sn=n/2(2a+d(n-1))

S28=28/2 (2(-143)+9(28-1))

S28=14(-286+9x27)

S28=14(-286+243)

S28=14(-43)

S28=-602