Please tell me how and work!!!
2 answers:
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Since 
, and you have a corresponding term in the given Riemann sum of 
, you know the integral is being taken over an interval of length 5, so you can omit the second choice.
Next,
corresponds to 
with 
. The fact that alone tells you that the interval of integration starts at 3, and since we know the interval has length 5, that leaves the first choice as the correct answer.
Next,
All you have to do, is combine like terms. Let's go through it:
Arrange it so you can easily combine like terms:
So, your answer for the sum is 1) 7x² - 10x + 2