If the diameter of a circle is changed from 5 cm to 10 cm, how will the circumference change? A) increases by a factor of 2 B) decreases by a factor of 2 C) increases by a factor of 5 D) decreases by a factor of 5

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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