document.write( "Question 677673: find the vertex of the parabola\r
\n" ); document.write( "\n" ); document.write( "F(x)=2x^2+8x+3\r
\n" ); document.write( "\n" ); document.write( "Can you please show the work so that I can get a full understanding.\r
\n" ); document.write( "\n" ); document.write( "Thank you
\n" ); document.write( "

Algebra.Com's Answer #421002 by josmiceli(19441)\"\" \"About 
You can put this solution on YOUR website!
\"+F%28x%29=2x%5E2%2B8x%2B3+\"
\n" ); document.write( "This is a parabola with a minimum and not a maximum
\n" ); document.write( "I can tell because the squared term is positive. If I changed it
\n" ); document.write( "to \"+F%28x%29=-2x%5E2%2B8x%2B3+\" then it would have a maximum.
\n" ); document.write( "The vertex is the (x,y) point at the minimum ( or maximum )
\n" ); document.write( "---------------
\n" ); document.write( "The x-coordinate of the vertex occurs halfway
\n" ); document.write( "between the roots, which are
\n" ); document.write( "the two solutions to \"+2x%5E2%2B8x%2B3+=+0+\"
\n" ); document.write( "---------------
\n" ); document.write( "To get a deeper understanding of this look at the
\n" ); document.write( "quadratic formula which gives these two solutions
\n" ); document.write( "---------------
\n" ); document.write( "\"+x%5B1%5D+=+%28-b+%2B+sqrt%28+b%5E2+-+4%2Aa%2Ac+%29%29+%2F+%282%2Aa%29+\"
\n" ); document.write( "\"+x%5B2%5D+=+%28-b+-+sqrt%28+b%5E2+-+4%2Aa%2Ac+%29%29+%2F+%282%2Aa%29+\"
\n" ); document.write( "Now I'll separate the terms in each solution:
\n" ); document.write( "\"+x%5B1%5D+=+-b%2F%282a%29+%2B+%28+sqrt%28+b%5E2+-+4%2Aa%2Ac%29+%29+%2F+%282%2Aa%29+\"
\n" ); document.write( "\"+x%5B2%5D+=+-b%2F%282a%29+-+%28+sqrt%28+b%5E2+-+4%2Aa%2Ac%29+%29+%2F+%282%2Aa%29+\"
\n" ); document.write( "-----------------------------------------
\n" ); document.write( "Now what you have is:
\n" ); document.write( "\"+x%5B1%5D+\" = ( x coordinate of the vertex ) + ( the positive correction )
\n" ); document.write( "\"+x%5B2%5D+\" = ( x coordinate of the vertex ) - ( the negative correction )
\n" ); document.write( "-------------------
\n" ); document.write( "So, you can see that \"+-b%2F%282a%29+\" is the x-coordinate of the vertex
\n" ); document.write( "when the form of the equation is \"+f%28x%29+=+ax%5E2+%2B+b%2Ax+%2B+c+\"
\n" ); document.write( "-------------------
\n" ); document.write( "I can apply this to your problem
\n" ); document.write( "\"+F%28x%29=2x%5E2%2B8x%2B3+\"
\n" ); document.write( "\"+a+=+2+\"
\n" ); document.write( "\"+b+=+8+\"
\n" ); document.write( "\"+c+=+3+\"
\n" ); document.write( "\"+-b%2F%282a%29+=+-8%2F%282%2A2%29+\"
\n" ); document.write( "\"+-b%2F%282a%29+=+-2+\"
\n" ); document.write( "--------------------
\n" ); document.write( "Now you know the vertex is at ( -2, y ). To find y, plug \"+x+=+-2+\"
\n" ); document.write( "into the equation
\n" ); document.write( "\"+y+=2%2A%28-2%29%5E2%2B8%2A%28-2%29%2B3+\"
\n" ); document.write( "\"+y+=+2%2A4+-+16+%2B+3+\"
\n" ); document.write( "\"+y+=+8+-+16+%2B+3+\"
\n" ); document.write( "\"+y+=+-5+\"
\n" ); document.write( "---------------
\n" ); document.write( "The vertex is at ( -2, -5 )
\n" ); document.write( "Here's a plot of the equation:
\n" ); document.write( "\"+graph%28+400%2C+400%2C+-7%2C+7%2C+-7%2C+7%2C+2x%5E2+%2B+8x+%2B+3+%29+\"
\n" ); document.write( "The vertex is where is should be\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );