What is the volume of a rectangular prism with a length of 2.5 cm, a width of 3.1 cm and a height of 1.2 cm? A. 7.75 cm³
B. 8.1 cm³
C. 8.3 cm³
D. 9.3 cm³

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