document.write( "Question 820174: PLEASE HELP!!! An ellipse has a center at (-4,6) and passes through (-4,9) and (2,6). Find the equation of the ellipse, the coordinates of the vertices and foci. \n" ); document.write( "
Algebra.Com's Answer #493446 by lwsshak3(11628)\"\" \"About 
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An ellipse has a center at (-4,6) and passes through (-4,9) and (2,6). Find the equation of the ellipse, the coordinates of the vertices and foci.
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\n" ); document.write( "Given coordinates show this is an ellipse with horizontal major axis.
\n" ); document.write( "Its standard form: \"%28x-h%29%5E2%2Fa%5E2%2B%28y-k%29%5E2%2Fb%5E2=1\",a>b, (h,k)=(x,y) coordinates of center.
\n" ); document.write( "..
\n" ); document.write( "\"%28x%2B4%29%5E2%2Fa%5E2%2B%28y-6%29%5E2%2Fb%5E2=1\"
\n" ); document.write( "plug in coordinates of one given point (-4,9) on the ellipse.
\n" ); document.write( "\"%28-4%2B4%29%5E2%2Fa%5E2%2B%289-6%29%5E2%2Fb%5E2=1\"
\n" ); document.write( "\"0%2B%283%29%5E2%2Fb%5E2=1\"
\n" ); document.write( "b^2=9
\n" ); document.write( "b=3
\n" ); document.write( "..
\n" ); document.write( "plug in coordinates of 2nd given point (2,6) on the ellipse.
\n" ); document.write( "\"%282%2B4%29%5E2%2Fa%5E2%2B%286-6%29%5E2%2Fb%5E2=1\"
\n" ); document.write( "\"%282%2B4%29%5E2%2Fa%5E2%2B0=1\"
\n" ); document.write( "\"%286%29%5E2%2Fa%5E2%2B0=1\"
\n" ); document.write( "a^2=36
\n" ); document.write( "a=6
\n" ); document.write( "..
\n" ); document.write( "equation of given ellipse:
\n" ); document.write( "\"%28x%2B4%29%5E2%2F36%2B%28y-6%29%5E2%2F9=1\"
\n" ); document.write( "..
\n" ); document.write( "vertices:(-4±a,6)=(4±6,6)=(-2,6) and (10,6)
\n" ); document.write( "c^2=a^2-b^2=36-9=27
\n" ); document.write( "c=√27≈5.2
\n" ); document.write( "..
\n" ); document.write( "foci:(-4±c,6)=(4±5.2,6)=(-1.2,6) and (9.2,6)\r
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