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

asked Apr 11, 2021 63.8k views

1 vote

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4 votes

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

Bitcodr answered Apr 16, 2021

4.9k points

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