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# halppppp

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Two points on a parabola are (-3,5) and (11,5). What is the equation of the axis of symmetry?

May 30, 2019

#1
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The axis of symmetry will  be found by adding the x coordinates of these points and dividing by 2......so

x  =  [ -3 + 11]  / 2

x  =  [ 8 ] / 2

x = 4   ⇒   axis of symmetry

May 30, 2019
#3
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why divide by 2?

ProffesorNobody  May 30, 2019
#2
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???? how does that work

May 30, 2019
edited by ProffesorNobody  May 30, 2019
#5
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This parabola opens upward

The axis of symmetry for a parabola that opens upward (or downward ) will  always  be the average of the two x values whenever those two x values are associated with the same y value

Thus...to find the average....add the x values and divide by 2

CPhill  May 30, 2019
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average....?

ProffesorNobody  May 30, 2019
edited by ProffesorNobody  May 30, 2019
#7
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does it work for the y to?

ProffesorNobody  May 30, 2019
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Yes....if we had   (4, 9)  and (4, 11).....the axis of symmetry would be

y =  [ 9 + 11 ] / 2  =  20 / 2   =  10

CPhill  May 30, 2019
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ok what is that method called?

ProffesorNobody  May 30, 2019
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Not sure it has a name......

CPhill  May 30, 2019
#13
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awwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwwww

ProffesorNobody  May 31, 2019
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how do you get points: sorry off topic

May 30, 2019
#8
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I think that anyone who is a member can give you points....I just gave you a few!!!!

CPhill  May 30, 2019
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YAY THX

ProffesorNobody  May 30, 2019