document.write( "Question 116801: consider the function: f(x)= x^2+6x-2. Find h, the x-coordinate of the vertex of this parabola. \n" ); document.write( "
Algebra.Com's Answer #84912 by bucky(2189)\"\" \"About 
You can put this solution on YOUR website!
Given:
\n" ); document.write( ".
\n" ); document.write( "\"f%28x%29=+x%5E2%2B6x-2\"
\n" ); document.write( ".
\n" ); document.write( "This function is of the standard form:
\n" ); document.write( ".
\n" ); document.write( "\"y+=+ax%5E2+%2B+bx+%2B+c\"
\n" ); document.write( ".
\n" ); document.write( "Recall the quadratic formula that says for a function of this form the solutions for x are:
\n" ); document.write( ".
\n" ); document.write( "\"x+=+-b%2F%282%2Aa%29+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%2F%282%2Aa%29+\"
\n" ); document.write( ".
\n" ); document.write( "The first term on the right side (that is \"-b%2F%282%2Aa%29\" will give you the value for x
\n" ); document.write( "at the vertex of the parabolic graph for \"y+=+ax%5E2+%2B+bx+%2B+c\"
\n" ); document.write( ".
\n" ); document.write( "Comparing the given function with the standard form you can see that a in the standard form
\n" ); document.write( "[the multiplier of the \"x%5E2\"] is +1 in the given problem, and b in the standard form
\n" ); document.write( "[the multiplier of the \"x\"] is +6 in the given problem, and c (which we don't need) in
\n" ); document.write( "the standard function is -2 in the given problem.
\n" ); document.write( ".
\n" ); document.write( "All you now have to do to solve this problem is plug the values for a and b into \"-b%2F%282%2Aa%29\"
\n" ); document.write( "and you get that the value of x at the vertex is:
\n" ); document.write( ".
\n" ); document.write( "\"-b%2F%282%2Aa%29+=+-%28%2B6%29%2F%282%2A1%29+=+-6%2F2+=+-3\"
\n" ); document.write( ".
\n" ); document.write( "So the answer to your problem is h = -3
\n" ); document.write( ".
\n" ); document.write( "Here's the graph of the equation \"y+=+x%5E2+%2B+6x+-2\" (shown in red) to help you validate
\n" ); document.write( "the answer. The green line is a vertical line through the vertex. It shows you that the
\n" ); document.write( "vertex has -3 as the value for its x:
\n" ); document.write( ".
\n" ); document.write( "\"graph%28400%2C400%2C-10%2C5%2C-15%2C5%2Cx%5E2+%2B6x+-2%2C3000%28x%2B3%29%2F3%29\"
\n" ); document.write( ".
\n" ); document.write( "Hope this helps you to understand the problem a little better.
\n" ); document.write( ".
\n" ); document.write( "
\n" );