Calculus integration?

Question

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the theorem "e" says:
If a ≤ b and f(x) ≤ g(x) for a ≤ x ≤ b, then
a a
∫ f(x) dx ≤ ∫ g(x) dx.
b b

Answer 1

Your integral lies between 15 and 20:

The value of your function is between 3 (min) and 4 (max). You are integrating over an interval of 5 units. Therefore, minimum is 3 * 5. Maximum is 4 * 5

Answer 2

The theorm indicates that the integration result will be equal to or greater than 15.