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How many y-intercepts does the graph of the parabola x = y^2 - 4y - 1 have?

 Oct 9, 2019
 #1
avatar+2649 
+1

2 y-intercepts

 

https://www.desmos.com/calculator/buaqjswt7y

 

This is because the equation forms an ellipse, and is in the ellipse form.

 Oct 9, 2019
 #2
avatar+107011 
+2

You're close, CU......this actually is a parabola that opens to the right

 

We can find the y intercepts by setting  x  = 0  and solving

 

y^2 - 4y  - 1   = 0

 

y^2 - 4y  =   1        complete the square on y

 

y^2 - 4y + 4  =   1 + 4

 

(y - 2)^2  =  5      take both roots

 

y - 2 = ±√5

 

y  =  2 ±√5

 

So.....there are two y intercepts  as shown by CU's  graph....!!!!

 

 

cool cool cool

 Oct 9, 2019

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