document.write( "Question 193531This question is from textbook algebra and trigonometry structure and method book 2
\n" ); document.write( ": Find the vertex, focus, directrix, and axis of symmetry of each parabola.
\n" ); document.write( "x^2+8y+4x-4=0
\n" ); document.write( "We have been using the formulas y-k=a(x-h)^2 and x-h=a(y-k)^2 I don't understand which to use here, even after completing the square and its confusing because I don't know which is which. please explain and be specific. thank you. \n" ); document.write( "

Algebra.Com's Answer #145268 by Mathtut(3670) $\"\"$ $\"About$

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$\"8y=-x%5E2-4x%2B4\"$
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\n" ); document.write( " $\"8y=-1%28x%5E2%2B4x%2B4%29%2B4-4\"$
\n" ); document.write( ":
\n" ); document.write( " $\"8y=-1%28x%2B2%29%5E2\"$
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\n" ); document.write( " $\"y=%28-1%2F8%29%28x%2B2%29%5E2\"$
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\n" ); document.write( "a=coefficient of $\"x%5E2\"$ term so a=-1/8
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\n" ); document.write( "so vertex is (-2,0)
\n" ); document.write( "focus is (-2,0+1/4a)-->1/4a=1/(4(-1/8)=1/(-1/2)=-2--> (-2,-2)
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\n" ); document.write( "directrix is at y=-1/4a=-1/4(-1/8)=-1/(-1/2)=2 so y=2
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\n" ); document.write( "axis of symmetry is x=-2
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\n" ); document.write( " $\"graph%28300%2C300%2C-10%2C10%2C-10%2C10%2C%28-1%2F8%29%28x%2B2%29%5E2%29\"$ \n" ); document.write( "

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