Determine the point(s) (if any) at which the graph of the function has a horizontal tangent line. ( f(x) = x^3 +15x^2 +3

step-by-step explanation:

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(2,20) means that the 2 is 2 hours and 20 is 20$. so there both 20$ for 2 hours only the same price. like it says. so, the dunk tank and the bounce house are the same price (20$) for the same amount of time (2 hours).

hope i