What is the value of f ( − 3a ), if f ( x ) = 2x 2 + 6x ?

select one: a. 18a 2 - 9a
b. 18a 2 - 18a
c. 9a 2 - 18a
d. 18a - 6a

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