Lei is renting a paddle board from a local shop that charges a $12 fee, plus an hourly rate of $8.50. For how long can Lei rent a paddle board if she pays a total of $80

positive

step-by-step explanation:

the quadrant is facing upwards

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