document.write( "Question 91926This question is from textbook Begining Algebra
\n" ); document.write( ": Hello,
\n" ); document.write( "Would you please help me with this problem:
\n" ); document.write( "Identify the axis of symetry, create a suitable table of values, and sketch th graph. y=-x^2+6x-2\r
\n" ); document.write( "\n" ); document.write( "This is how far I have gotten, but I am not too sure if I have gotten this part right.
\n" ); document.write( "y=-x^2+6x-2
\n" ); document.write( "y+2=-x^2+6x
\n" ); document.write( "y+2+9=x^2+6x+9
\n" ); document.write( "y+11=(x+3)^2
\n" ); document.write( "Can you please walk me through how to complete this type of problem?
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Algebra.Com's Answer #66796 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
\"y=-x%5E2%2B6x-2\" Start with the given quadratic\r
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\n" ); document.write( "\n" ); document.write( "\"y%2B2=-x%5E2%2B6x\" Add \"2++\" to both sides\r
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\n" ); document.write( "\n" ); document.write( "\"y%2B2=-1%2A%28x%5E2-6%2Ax%29\" Factor out the leading coefficient \"-1++\". This step is important since we want the \"x%5E2\" coefficient to be 1. This is where you made your mistake\r
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\n" ); document.write( "\n" ); document.write( "Take half of the x coefficient \"-6\" to get \"-3\" (ie \"-6%2F2=-3\")\r
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\n" ); document.write( "\n" ); document.write( "Now square \"-3\" to get \"9\" (ie \"%28-3%29%5E2=9\")\r
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\n" ); document.write( "\n" ); document.write( "\"y%2B2=-1%2A%28x%5E2-6%2Ax%2B9%29\" Add this number (\"9\") to the expression inside the parenthesis.\r
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\n" ); document.write( "\n" ); document.write( "\"y%2B2%2B%28-1%29%289%29=-1%2A%28x%5E2-6%2Ax%2B9%29\" Since we added \"9\" inside the parenthesis, we need to add \"%28-1%29%289%29\" to the other side (remember, we factored out the leading coefficient \"-1\").\r
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\n" ); document.write( "\n" ); document.write( "\"y%2B2%2B%28-1%29%289%29=-1%2A%28x-3%29%5E2\" Factor \"x%5E2-6%2Ax%2B9\" into \"%28x-3%29%5E2\". Now the right side is a perfect square (note: if you need help with factoring, check out this solver)\r
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\n" ); document.write( "\n" ); document.write( "\"y%2B2-9=-1%2A%28x-3%29%5E2\" Multiply \"-1\" and \"9\" to get \"-9\".\r
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\n" ); document.write( "\n" ); document.write( "\"y-7=-1%2A%28x-3%29%5E2\" Combine like terms\r
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\n" ); document.write( "\n" ); document.write( "\"y=-1%2A%28x-3%29%5E2%2B7\"Add \"7++\" to both sides to isolate y\r
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\n" ); document.write( "\n" ); document.write( "Now the quadratic \"y=-1%2A%28x-3%29%5E2%2B7\" is in vertex form \"y=a%28x-h%29%5E2%2Bk\" where \"a=-1\", \"h=3\", and \"k=7\"\r
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\n" ); document.write( "\n" ); document.write( "Remember, for any quadratic in vertex form \"y=a%28x-h%29%5E2%2Bk\" the vertex is (h,k) and the axis of symmetry is x=h\r
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\n" ); document.write( "\n" ); document.write( "So the vertex is (\"3\",\"7\") and the axis of symmetry is x=3\r
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\n" ); document.write( "\n" ); document.write( "In order to create a table of suitable values, simply plug in x-values that are close to the axis of symmetry.\r
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\n" ); document.write( "\n" ); document.write( "For instance, plug in x=1 (which is two units away from the axis of symmetry) to get y=3. So our first point is (1,3)\r
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\n" ); document.write( "\n" ); document.write( "Now plug in x=2 (which is one unit away from the axis of symmetry) to get y=6. That makes our second point (2,6).\r
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\n" ); document.write( "\n" ); document.write( "Since we know the vertex is (3,7), our third point is (3,7)\r
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\n" ); document.write( "\n" ); document.write( "Since the graph is symmetric with respect to the axis of symmetry, the x-value that is one unit to the right of the axis of symmetry (x=4) will have the same y-value as x=2 (since x=2 is also one unit away from the axis of symmetry). So our fourth point is (4,6)\r
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\n" ); document.write( "\n" ); document.write( "Also the x-value that is two units to the right of the axis of symmetry (x=5) will have the same y-value as x=1 (since x=1 is also two units away from the axis of symmetry). This makes our fifth point at (5,3)\r
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\n" ); document.write( "\n" ); document.write( "So our table looks like\r
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x
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y
1| 3
2| 6
3| 7
4| 6
5| 3
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\n" ); document.write( "\n" ); document.write( "Now plot the points\r
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\n" ); document.write( "\n" ); document.write( "Now connect the points to graph \"y=-x%5E2%2B6x-2\"\r
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