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The parabola y = x^2 + bx + c has a vertex at (-4,8).  Find b + c.

 Jan 27, 2021

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 #1
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Similarto other Q's asked this day:

 

axis of symmetry is  x = -4    ( from vertex)

 

this is given by   x = -b/2a

                          -4 = -b/2   so b = 8

 

x^2 + 8x + c     has the point   -4,8     sub this in to calculate  'c'

(-4)^2 + 8 (-4) + c = 8

  16 -32 + c = 8

    c = 24                            Now  add   b + c .................

 Jan 27, 2021
 #1
avatar
+1
Best Answer

Similarto other Q's asked this day:

 

axis of symmetry is  x = -4    ( from vertex)

 

this is given by   x = -b/2a

                          -4 = -b/2   so b = 8

 

x^2 + 8x + c     has the point   -4,8     sub this in to calculate  'c'

(-4)^2 + 8 (-4) + c = 8

  16 -32 + c = 8

    c = 24                            Now  add   b + c .................

Guest Jan 27, 2021

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