Help me please, please

The Answer is D

D.) r=16.68

Step-by-step explanation:

So i did was 19.68+80 so that equal = 99.68. Then i did 16.68+80. Then that equal the same as 99.68.

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