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Find the vertex of the graph of the equation $y = -2x^2+8x-15$, I've tried this problem and I got (-2, -23) every time, I don't see where I'm going wrong, I need some help with this problem.

 Jul 2, 2021
 #1
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When you plug in x = -2, you get -39, so the vertex is (-2,-39).

 Jul 2, 2021
 #4
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ur wrong

Guest Jul 2, 2021
 #2
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The x coordinate of this dome shaped parabola's vertex will be given by   x = - b/2a      where b = 8     and   a = -  2     

 

      x = 2

 

use this value in the equation to calculate the y coordinate as   - 7

 Jul 2, 2021
edited by ElectricPavlov  Jul 2, 2021
 #3
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vertex is (2, -7)

 Jul 2, 2021
 #5
avatar+320 
+4

Hey there, ICL!

 

So, sometimes when you can't solve an equation, you can plug it into a Desmos Graphing Calc and then you'll be able to see the vertex.

 

EP is right about this one, x=2 and y= -7; here's the link to the graph: https://www.desmos.com/calculator/9nnq18slcn.

 

Hope this helped! :)

( ゚д゚)つ Bye

 Jul 2, 2021

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