Answer
$80$
Work Step by Step
We expand the sum:
$\displaystyle \sum_{i=4}^{8}(3i-2)$
$=[3(4)-2]+[3(5)-2]+[3(6)-2]+[3(7)-2]+[3(8)-2]$
$=(12-2)+(15-2)+(18-2)+(21-2)+(24-2)$
$=10+13+16+19+22$
$=80$
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