The graph represents the function where electricity usage in kilowatts per hour of a clock radio varies directly with the number of days it is plugged into the wall current. A coordinate grid showing Clock Radio Electricity Usage, with Days Connected to Current on the x-axis and Electricity Usage in kilowatt hours on the y-axis with a line starting at (0, 0) and passing through (2, 0.5) and (6, 1.5).
Which is a reasonable estimate of the constant of variation?

0.25 kWh per day
0.50 kWh per day
2.40 kWh per day
4.00 kWh per day

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

step-by-step explanation:

use context clues to figure out the meaning of the bolded word:  

the sage gardener knew when she had to water her plants.  

question 8 options:

mint plant

wise

happy

lazy