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Question 498546:  x2 − 2y = 8x −10 what is the focus and focus width of this parabola? 
 Answer by lwsshak3(11628)      (Show Source): 
You can  put this solution on YOUR website! x2 − 2y = 8x −10 what is the focus and focus width of this parabola? 
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x2 − 2y = 8x −10 
2y=x^2-8x+10 
complete the square 
2y=(x^2-8x+16)+10-16 
2y=(x-4)^2-6 
(x-4)^2=2y+6=2(y+3) 
(x-4)^2=2(y+3) 
Standard form for equation of this parabola: (x-h)^2=4p(y-k), (h,k) being the (x,y) coordinates of the vertex and parabola opens upwards. 
For given equation of parabola: 
vertex: (4,-3) 
axis of symmetry: x=4 
4p=2 
p=2/4=1/2 
focus: (4, 5/2) 
focal width: 4p=2 
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