Use a graphing calculator or other technology to answer the question.
Which quadratic regression equation best fits the data set?


y
ˆ
=2.608
x
2
+115.265x+1568.065


y
ˆ
=2.608
x
2
−115.265x+1568.065


y
ˆ
=1568.065
x
2
−115.265x+2.608


y
ˆ
=1568.065
x
2
+115.265x+2.608
x
y
15
423
17
398
19
308
20
255
21
297
25
365
29
401

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

the answer to this is a. a^2 + b^2 = c^2