Janet surveyed a class or students she recorded the number of hours that each student volunteered this line plot shows the resul
ts of the survey
1 answer:
You might be interested in
Answer:
Step-by-step explanation:
Answer:
option C ⇒ C) y = -x² + 18x - 74
Step-by-step explanation:
The given options are:
A) y = -x² + 14x - 40
B) y = -x² - 18x - 88
C) y = -x² + 18x - 74
D) y = -x² - 14x - 58
=================================
The general equation of the parabola has the form:
y = f(x) = ax² + bx + c
The vertex of the parabola has the coordinates (h , k)
where h =
and k = f(h) = f()
Check option A: a = -1 , b = 14 ⇒ (h,k) = (7, f(7) ) = (7 , 9)
Check option B: a = -1 , b = -18 ⇒ (h,k) = (-9, f(-9) ) = (-9,-7)
Check option C: a = -1 , b = 18 ⇒ (h,k) = (9, f(9) ) = (9,7)
Check option D: a = -1 , b = -14 ⇒ (h,k) = (-7, f(7) ) = (-7,-9)
So the equation which has a maximum at (9,7) ⇒ y = -x² + 18x - 74
<u>So, the correct answer is option C</u>