document.write( "Question 79162: Can someone help me with this problem? I'm stuck!!! I'm in a class that is over my head. Help!!!!!!!!!!!!!!!!!!!!\r
\n" ); document.write( "\n" ); document.write( "For the function y = x2 - 6x + 8, perform the following tasks:
\n" ); document.write( "a) Put the function in the form y = a(x - h)2 + k.
\n" ); document.write( "Answer:
\n" ); document.write( "Show work in this space. \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "b) What is the equation for the line of symmetry for the graph of this function?
\n" ); document.write( "Answer: \r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "c) Graph the function using the equation in part a. Explain why it is not necessary to plot points to graph when using y = a (x - h) 2 + k.
\n" ); document.write( "Show graph here. \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Explanation of graphing. \r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "d) In your own words, describe how this graph compares to the graph of y = x2?
\n" ); document.write( "Answer: \r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #56824 by Earlsdon(6294)\"\" \"About 
You can put this solution on YOUR website!
a) Put the function\"y+=+x%5E2-6x%2B8\" into the form \"y+=+a%28x-h%29%5E2%2Bk\"
\n" ); document.write( "To do this you will start with the given function and you will \"complete the square\".\r
\n" ); document.write( "\n" ); document.write( "\"y+=+x%5E2-6x%2B8\" Now subtract the constant (8) from both sides.
\n" ); document.write( "\"y-8+=+x%5E2-6x\" Now complete the square in the x-terms by adding the square of half the x-coefficient (that's \"%28-6%2F2%29%5E2+=+9\") to both sides.
\n" ); document.write( "\"y%2B1+=+x%5E2-6x%2B9\" Factor the right side.
\n" ); document.write( "\"y%2B1+=+%28x-3%29%5E2\" Now subtract 1 from both sides.
\n" ); document.write( "\"y+=+%28x-3%29%5E2-1\" Compare this with:
\n" ); document.write( "\"y+=+a%28x-h%29%5E2%2Bk\"
\n" ); document.write( "a = 1
\n" ); document.write( "h = 3
\n" ); document.write( "k = -1\r
\n" ); document.write( "\n" ); document.write( "b) The equation of the line of symmetry is given by:
\n" ); document.write( "\"x+=+h\", so in this case, since h = 3, the equation of the line of symmetry is:
\n" ); document.write( "\"x+=+3\" This is a vertical line passing through the point (3, 0)\r
\n" ); document.write( "\n" ); document.write( "c) It is not necessary to plot points to graph the function in this form because:
\n" ); document.write( "1) You know the equation of the line of symmetry.
\n" ); document.write( "2) You know that the parabola opens upward because a>0 (a is positive).
\n" ); document.write( "3) You know (or can find) the location of the vertex of the parabola. Thi is given by (h, k) or (3, -1)
\n" ); document.write( "4) You can find the x- and y-intercepts of the function by:
\n" ); document.write( "x-intercepts: Set y = 0 and solve for x.
\n" ); document.write( "\"%28x-3%29%5E2-1+=+0\" Add 1 to both sides.
\n" ); document.write( "\"%28x-3%29%5E2+=+1\" Take the square root of both sides.
\n" ); document.write( "\"sqrt%28x-3%29%5E2+=+sqrt%281%29\"
\n" ); document.write( "\"x-3+=+1\" + or - Add 3 to both sides.
\n" ); document.write( "\"x+=+3%2B1\" and \"x+=+3-1\"
\n" ); document.write( "\"x+=+4\" and \"x+=+2\" These are the x-intercepts.
\n" ); document.write( "y-intercept: Set x = 0 and solve for y.
\n" ); document.write( "\"y+=+%280-3%29%5E2+-1\"
\n" ); document.write( "\"y+=+9-1\"
\n" ); document.write( "\"y+=+8\" This the y-intecept.\r
\n" ); document.write( "\n" ); document.write( "Here is the graph (in red): I'll add the graph of the function \"y+=+x%5E2\" (in green) so you can compare the two.
\n" ); document.write( "\"graph%28300%2C200%2C-5%2C6%2C-4%2C10%2C%28x-3%29%5E2-1%2Cx%5E2%29\"\r
\n" ); document.write( "\n" ); document.write( "d) I'll leave the explanation to you. Look at the two graphs and try to see what effects the values of h and k have on the placement of the second (green) graph compared to the first (red) graph.
\n" ); document.write( "
\n" ); document.write( "
\n" );