1. The monthly fee for a cellphone is b dollars but they gave a 20% discount if the contract was renewed this month. What is this month's
bill?
O A. 0.80b
O B. b-0.20
O C.6-20
O D. 0.206

the least common denominator is 40

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