Determine the intervals on which the function is increasing, decreasing, and constant. A. Increasing x>0; Decreasing x<0

B. Decreasing on all real numbers

C. Increasing on all real numbers

D. Increasing x<0; Decreasing x>0

Option A, increasing x>0; decreasing x<0

answer: 204

step-by-step explanation:

we are told that the revenue is

x⋅(4080−10x)=−10x^2+4080x

this is a quadratic function, so to maximize it we should find the x-value of its vertex. recall that the x-value of the vertex of the parabola ax^2+bx+c is given by the formula −b/2a.

so in this case, we have a=−10 and b=4080, so the x-value of the vertex is

−b/2a= −(4080)/2(−10)=204