Answer: 234
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Explanation:
The symbol that looks like an "E" is the uppercase greek letter sigma. It's used for summation. Specifically we are adding terms of the form -4+5n. What we do is replace n with values from the set {2,3,4,...,9,10}. After evaluating each item, we add up the results to get our final answer.
If n = 2, then -4+5n = -4+5*2 = 6 which is the first term.
If n = 3, then -4+5n = -4+5*3 = 11 is the second term
and so on until you reach n = 10.
A table is a handy way to keep track of everything (see below). Adding everything in the second column leads to the final answer of 234.
