SOLUTION: please help me learn how to solve this: State the coordinates of the vertex in the relation y^2 = 2x+4

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: please help me learn how to solve this: State the coordinates of the vertex in the relation y^2 = 2x+4      Log On


   



Question 973817: please help me learn how to solve this:
State the coordinates of the vertex in the relation y^2 = 2x+4

Answer by Edwin McCravy(20056) About Me  (Show Source):
You can put this solution on YOUR website!
The standard form for a parabola with a y2 term is

a%28y-k%29%5E2%22%22=%22%22x-h where (h,k) is the vertex 
   
We can get 

y%5E2%22%22=%22%222x%2B4 

in standard form: 

Write y as (y-0)

%28y-0%29%5E2%22%22=%22%222x%2B4

Factor out 2 on the right:

%28y-0%29%5E2%22%22=%22%222%28x%2B2%29
 
Multiply both sides by 1%2F2

expr%281%2F2%29%28y-0%29%5E2%22%22=%22%22expr%281%2F2%292%28x%2B2%29

expr%281%2F2%29%28y-0%29%5E2%22%22=%22%22expr%281%2Fcross%282%29%29cross%282%29%28x%2B2%29

expr%281%2F2%29%28y-0%29%5E2%22%22=%22%22x%2B2

Compare to

a%28y-k%29%5E2%22%22=%22%22x-h

-k=-0,  a=1/2,  -h=+2
 k=0             h=-2

So the vertex is (h,k) = (-2,0), the point where the big dot is
in the graph below:



Edwin