document.write( "Question 119297: What is the standard form for y=1/2x^2+4x-3 ? \n" ); document.write( "
Algebra.Com's Answer #87399 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
\n" ); document.write( "\n" ); document.write( " \n" ); document.write( "\n" ); document.write( "
Solved by pluggable solver: Completing the Square to Get a Quadratic into Vertex Form

\n" ); document.write( "
\n" ); document.write( " \"y=%281%2F2%29+x%5E2%2B4+x-3\" Start with the given equation
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y%2B3=%281%2F2%29+x%5E2%2B4+x\" Add \"3\" to both sides
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y%2B3=%281%2F2%29%28x%5E2%2B8x%29\" Factor out the leading coefficient \"%281%2F2%29\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Take half of the x coefficient \"8\" to get \"4\" (ie \"%281%2F2%29%288%29=4\").
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Now square \"4\" to get \"16\" (ie \"%284%29%5E2=%284%29%284%29=16\")
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y%2B3=%281%2F2%29%28x%5E2%2B8x%2B16-16%29\" Now add and subtract this value inside the parenthesis. Doing both the addition and subtraction of \"16\" does not change the equation
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y%2B3=%281%2F2%29%28%28x%2B4%29%5E2-16%29\" Now factor \"x%5E2%2B8x%2B16\" to get \"%28x%2B4%29%5E2\"
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y%2B3=%281%2F2%29%28x%2B4%29%5E2-%281%2F2%29%2816%29\" Distribute
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y%2B3=%281%2F2%29%28x%2B4%29%5E2-8\" Multiply
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y=%281%2F2%29%28x%2B4%29%5E2-8-3\" Now add \"%2B3\" to both sides to isolate y
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"y=%281%2F2%29%28x%2B4%29%5E2-11\" Combine like terms
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Now the quadratic is in vertex form \"y=a%28x-h%29%5E2%2Bk\" where \"a=1%2F2\", \"h=-4\", and \"k=-11\". Remember (h,k) is the vertex and \"a\" is the stretch/compression factor.
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Check:
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Notice if we graph the original equation \"y=%281%2F2%29x%5E2%2B4x-3\" we get:
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C%281%2F2%29x%5E2%2B4x-3%29\" Graph of \"y=%281%2F2%29x%5E2%2B4x-3\". Notice how the vertex is (\"-4\",\"-11\").
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " Notice if we graph the final equation \"y=%281%2F2%29%28x%2B4%29%5E2-11\" we get:
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " \"graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C%281%2F2%29%28x%2B4%29%5E2-11%29\" Graph of \"y=%281%2F2%29%28x%2B4%29%5E2-11\". Notice how the vertex is also (\"-4\",\"-11\").
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( " So if these two equations were graphed on the same coordinate plane, one would overlap another perfectly. So this visually verifies our answer.
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" );