document.write( "Question 752747: Hi, I'm having trouble figuring out a parabola's equation. The Y intercept is (0,6), the vertex is (2,8). These are the only points given. Can you please explain to me how to work out the equation/what it is?\r
\n" ); document.write( "\n" ); document.write( "Thanks a lot,
\n" ); document.write( "Nathan
\n" ); document.write( "

Algebra.Com's Answer #458002 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
The general form is
\n" ); document.write( "\"+y+=+a%2Ax%5E2+%2B+b%2Ax+%2B+c+\"
\n" ); document.write( "where \"+c+\" is the y-intercept,
\n" ); document.write( "(0,6),so now you have
\n" ); document.write( "\"+y+=+a%2Ax%5E2+%2B+b%2Ax+%2B+6+\"
\n" ); document.write( "The x-coordinate of the vertex,
\n" ); document.write( "(2,8), is \"+x%5Bv%5D+=+-b%2F%282a%29+\", so
\n" ); document.write( "\"+2+=+-b%2F%282a%29+\"
\n" ); document.write( "\"+4a+=+-b+\"
\n" ); document.write( "\"+b+=+-4a+\"
\n" ); document.write( "So far, you have:
\n" ); document.write( "\"+y+=+a%2Ax%5E2+-+4a%2Ax+%2B+6+\"
\n" ); document.write( "Now plug in the point ( 2,8 )
\n" ); document.write( "\"+8+=+a%2A2%5E2+-+4a%2A2+%2B+6+\"
\n" ); document.write( "\"+8+=+4a+-+8a+%2B+6+\"
\n" ); document.write( "\"+8+=+-4a+%2B+6+\"
\n" ); document.write( "\"+4a+=+-2+\"
\n" ); document.write( "\"+a+=+-1%2F2+\"
\n" ); document.write( "and
\n" ); document.write( "\"+b+=+-4a+\"
\n" ); document.write( "\"+b=+2+\"
\n" ); document.write( "------------
\n" ); document.write( "\"+y+=+a%2Ax%5E2+%2B+b%2Ax+%2B+c+\"
\n" ); document.write( "\"+y+=+%28-1%2F2%29%2Ax%5E2+%2B+2x+%2B+6+\" answer
\n" ); document.write( "--------------------------
\n" ); document.write( "Is the vertex at (2,8) ?
\n" ); document.write( "\"+x%5Bv%5D+=+2+\"
\n" ); document.write( "\"+2+=+-b%2F%282a%29+\"
\n" ); document.write( "\"+2+=+-2%2F%282%2A%28-1%2F2%29%29+\"
\n" ); document.write( "\"+2+=+2+\"
\n" ); document.write( "and
\n" ); document.write( "\"+8+=+%28-1%2F2%29%2A2%5E2+%2B+2%2A2+%2B+6+\"
\n" ); document.write( "\"+8+=+%28-1%2F2%29%2A4+%2B+4+%2B+6+\"
\n" ); document.write( "\"+8+=+-2+%2B+10+\"
\n" ); document.write( "\"+8+=+8+\"
\n" ); document.write( "OK
\n" ); document.write( "Here's a plot of the equation:
\n" ); document.write( "\"+graph%28+400%2C+400%2C+-10%2C+10%2C+-10%2C+10%2C++%28-1%2F2%29%2Ax%5E2+%2B+2x+%2B+6+%29+\"\r
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