Which of the following uses a variable to represent a person, place, or thing
that is unknown?
a. a c-sharp on the piano
b. apartment 12a
c. a b+ grade
d. mr. x

the answer is 4.8 units on e2020.

can someone answer this question plz

step-by-step explanation:

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