document.write( "Question 783360: What is the vertex, focus and directrix of the following:
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document.write( "4y^2+4x+4y-3=0
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document.write( "2x^2-12X+3y+21=0 \n" );
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Algebra.Com's Answer #476819 by lwsshak3(11628)![]() ![]() ![]() You can put this solution on YOUR website! What is the vertex, focus and directrix of the following: \n" ); document.write( "4y^2+4x+4y-3=0 \n" ); document.write( "4y^2+4y+4x-3=0 \n" ); document.write( "complete the square \n" ); document.write( "4(y^2+y+1/4)-1+4x-3=0 \n" ); document.write( "4(y+1/2)^2=-4x+4 \n" ); document.write( "4(y+1/2)^2=-4(x-1) \n" ); document.write( "divide by 4 \n" ); document.write( "(y+1/2)^2=-(x-1) \n" ); document.write( "This is a parabola that opens leftward. \n" ); document.write( "Its basic form of equation: (y+k)^2=-4p(x-h), (h,k)=(x,y) coordinates of the vertex \n" ); document.write( "For given equation: \n" ); document.write( "vertex: (1,-1/2) \n" ); document.write( "axis of symmetry: y=-1/2 \n" ); document.write( "4p=1 \n" ); document.write( "p=1/4 \n" ); document.write( "focus: (3/4,-1/2) (p-distance left of vertex on the axis of symmetry \n" ); document.write( "directrix: x=5/4 (p-distance right of vertex on the axis of symmetry \n" ); document.write( ".. \n" ); document.write( "2x^2-12x+3y+21=0 \n" ); document.write( "complete the square \n" ); document.write( "2(x^2-6x+9)-18+3y+21=0 \n" ); document.write( "2(x-3)^2=-3y+3 \n" ); document.write( "2(x-3)^2=-3(y+1) \n" ); document.write( "(x-3)^2=-3/2(y+1) \n" ); document.write( "This is a parabola that opens downward. \n" ); document.write( "Its basic form of equation: (x-h)^2=-4p(y-k), (h,k)=(x,y) coordinates of the vertex \n" ); document.write( "For given equation: \n" ); document.write( "vertex: (3,-1) \n" ); document.write( "axis of symmetry: x=3 \n" ); document.write( "4p=3/2 \n" ); document.write( "p=3/8 \n" ); document.write( "focus: (3,-11/8) (p-distance below vertex on the axis of symmetry \n" ); document.write( "directrix: y=-5/8 (p-distance above vertex on the axis of symmetry \n" ); document.write( ".. \n" ); document.write( " |