document.write( "Question 79924: 4x^2+40x+97 tell me the vertex and line of symmetry \n" ); document.write( "
Algebra.Com's Answer #57316 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Check out this solver for more problems dealing with the vertex and axis of symmetry. \r
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Solved by pluggable solver: Completing the Square to Get a Quadratic into Vertex Form

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\n" ); document.write( " \"y=4+x%5E2%2B40+x%2B97\" Start with the given equation
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\n" ); document.write( " \"y-97=4+x%5E2%2B40+x\" Subtract \"97\" from both sides
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\n" ); document.write( " \"y-97=4%28x%5E2%2B10x%29\" Factor out the leading coefficient \"4\"
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\n" ); document.write( " Take half of the x coefficient \"10\" to get \"5\" (ie \"%281%2F2%29%2810%29=5\").
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\n" ); document.write( " Now square \"5\" to get \"25\" (ie \"%285%29%5E2=%285%29%285%29=25\")
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\n" ); document.write( " \"y-97=4%28x%5E2%2B10x%2B25-25%29\" Now add and subtract this value inside the parenthesis. Doing both the addition and subtraction of \"25\" does not change the equation
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\n" ); document.write( " \"y-97=4%28%28x%2B5%29%5E2-25%29\" Now factor \"x%5E2%2B10x%2B25\" to get \"%28x%2B5%29%5E2\"
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\n" ); document.write( " \"y-97=4%28x%2B5%29%5E2-4%2825%29\" Distribute
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\n" ); document.write( " \"y-97=4%28x%2B5%29%5E2-100\" Multiply
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\n" ); document.write( " \"y=4%28x%2B5%29%5E2-100%2B97\" Now add \"97\" to both sides to isolate y
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\n" ); document.write( " \"y=4%28x%2B5%29%5E2-3\" Combine like terms
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\n" ); document.write( " Now the quadratic is in vertex form \"y=a%28x-h%29%5E2%2Bk\" where \"a=4\", \"h=-5\", and \"k=-3\". Remember (h,k) is the vertex and \"a\" is the stretch/compression factor.
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\n" ); document.write( " Check:
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\n" ); document.write( " Notice if we graph the original equation \"y=4x%5E2%2B40x%2B97\" we get:
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\n" ); document.write( " \"graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C4x%5E2%2B40x%2B97%29\" Graph of \"y=4x%5E2%2B40x%2B97\". Notice how the vertex is (\"-5\",\"-3\").
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\n" ); document.write( " Notice if we graph the final equation \"y=4%28x%2B5%29%5E2-3\" we get:
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\n" ); document.write( " \"graph%28500%2C500%2C-10%2C10%2C-10%2C10%2C4%28x%2B5%29%5E2-3%29\" Graph of \"y=4%28x%2B5%29%5E2-3\". Notice how the vertex is also (\"-5\",\"-3\").
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\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.
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