document.write( "Question 204503: \n" ); document.write( "
Algebra.Com's Answer #154379 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
# 1\r
\n" ); document.write( "\n" ); document.write( "\"f%28x%29=x%5E2%2B3\" Start with the given function\r
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\n" ); document.write( "\n" ); document.write( "\"f%28x%2Bh%29=%28x%2Bh%29%5E2%2B3\" Replace each \"x\" with \"x+h\"\r
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\n" ); document.write( "\n" ); document.write( "\"f%28x%2Bh%29=x%5E2%2B2xh%2Bh%5E2%2B3\" FOIL (ie expand)\r
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\n" ); document.write( "\n" ); document.write( "\"%28f%28x%2Bh%29-f%28x%29%29%2Fh\" Move onto the given difference quotient.\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%5E2%2B2xh%2Bh%5E2%2B3-%28x%5E2%2B3%29%29%2Fh\" Plug in \"f%28x%2Bh%29=x%5E2%2B2xh%2Bh%5E2%2B3\" and \"f%28x%29=x%5E2%2B3\"\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%5E2%2B2xh%2Bh%5E2%2B3-x%5E2-3%29%2Fh\" Distribute\r
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\n" ); document.write( "\n" ); document.write( "\"%282xh%2Bh%5E2%29%2Fh\" Combine like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"%28h%282x%2Bh%29%29%2Fh\" Factor out the GCF \"h\" from the numerator.\r
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\n" ); document.write( "\n" ); document.write( "\"%28cross%28h%29%282x%2Bh%29%29%2Fcross%28h%29\" Cancel out the common terms.\r
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\n" ); document.write( "\n" ); document.write( "\"2x%2Bh\" Simplify\r
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\n" ); document.write( "\n" ); document.write( "So \"%28f%28x%2Bh%29-f%28x%29%29%2Fh=2x%2Bh\" when \"f%28x%29=x%5E2%2B3\"\r
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\n" ); document.write( "\n" ); document.write( "# 2\r
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\n" ); document.write( "\n" ); document.write( "Take note that when \"x=-3\" it is less than zero. Because \"f%28x%29=-x\" when \"x%3C0\", this means that we simply plug in \"x=-3\" to get: \"f%28-3%29=-%28-3%29=3\". \r
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\n" ); document.write( "\n" ); document.write( "So \"f%28-3%29=3\"\r
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\n" ); document.write( "\n" ); document.write( "Also, when \"x=2\" it is greater than zero. Since \"f%28x%29=x%5E3\" when \"x%3E=0\", we just plug in \"x=2\" to get: \"f%282%29=%282%29%5E3=8\".\r
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\n" ); document.write( "\n" ); document.write( "So \"f%282%29=8\"\r
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\n" ); document.write( "\n" ); document.write( "# 3\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B2y-3=0\" Start with the given equation.\r
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\n" ); document.write( "\n" ); document.write( "\"x%2B2y=3\" Add 3 to both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"2y=3-x\" Subtract \"x\" from both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"2y=-x%2B3\" Rearrange the terms.\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-x%2B3%29%2F2\" Divide both sides by \"2\" to isolate y.\r
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\n" ); document.write( "\n" ); document.write( "\"y=-%281%2F2%29x%2B3%2F2\" Break up the fraction and simplify.\r
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\n" ); document.write( "\n" ); document.write( "We can see that the equation \"y=-%281%2F2%29x%2B3%2F2\" has a slope \"m=-1%2F2\" and a y-intercept \"b=3%2F2\".\r
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\n" ); document.write( "\n" ); document.write( "Now to find the slope of the perpendicular line, simply flip the slope \"m=-1%2F2\" to get \"m=-2%2F1\". Now change the sign to get \"m=2\". So the perpendicular slope is \"m=2\".\r
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\n" ); document.write( "\n" ); document.write( "Now let's use the point slope formula to find the equation of the perpendicular line by plugging in the slope \"m=-1%2F2\" and the coordinates of the given point .\r
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\n" ); document.write( "\n" ); document.write( "\"y-y%5B1%5D=m%28x-x%5B1%5D%29\" Start with the point slope formula\r
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\n" ); document.write( "\n" ); document.write( "\"y--4=2%28x-6%29\" Plug in \"m=2\", \"x%5B1%5D=6\", and \"y%5B1%5D=-4\"\r
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\n" ); document.write( "\n" ); document.write( "\"y%2B4=2%28x-6%29\" Rewrite \"y--4\" as \"y%2B4\"\r
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\n" ); document.write( "\n" ); document.write( "\"y%2B4=2x%2B2%28-6%29\" Distribute\r
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\n" ); document.write( "\n" ); document.write( "\"y%2B4=2x-12\" Multiply\r
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\n" ); document.write( "\n" ); document.write( "\"y=2x-12-4\" Subtract 4 from both sides. \r
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\n" ); document.write( "\n" ); document.write( "\"y=2x-16\" Combine like terms. \r
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\n" ); document.write( "\n" ); document.write( "So the equation of the line perpendicular to \"x%2B2y-3=0\" that goes through the point is \"y=2x-16\".\r
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\n" ); document.write( "\n" ); document.write( "Here's a graph to visually verify our answer:\r
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\n" ); document.write( "\n" ); document.write( "Graph of the original equation \"x%2B2y-3=0\" (red) and the perpendicular line \"y=2x-16\" (green) through the point . \r
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\n" ); document.write( "\n" ); document.write( "# 5\r
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\n" ); document.write( "\n" ); document.write( "\"x%5E2-8x%2By%5E2-6y=0\" Start with the given equation\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%5E2-8x%29%2B%28y%5E2-6y%29=0\" Group like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%5E2-8x%2Bhighlight%2816%29%29%2B%28y%5E2-6y%29=0%2Bhighlight%2816%29\" Take half of the x-coefficient -8 to get -4. Square -4 to get 16. Add this value to both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"%28x%5E2-8x%2B16%29%2B%28y%5E2-6y%2Bhighlight%289%29%29=0%2B16%2Bhighlight%289%29\" Take half of the y-coefficient -6 to get -3. Square -3 to get 9. Add this value to both sides.\r
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\n" ); document.write( "\n" ); document.write( "\"%28x-4%29%5E2%2B%28y-3%29%5E2=25\" Combine like terms.\r
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\n" ); document.write( "\n" ); document.write( "\"%28x-4%29%5E2%2B%28y-3%29%5E2=5%5E2\" Rewrite 25 as \"5%5E2\"\r
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\n" ); document.write( "\n" ); document.write( "Now the equation is in the form \"%28x-h%29%5E2%2B%28y-k%29%5E2=r%5E2\" (which is a circle) where (h,k) is the center and \"r\" is the radius\r
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\n" ); document.write( "\n" ); document.write( "In this case, \"h=4\", \"k=3\", and \"r=5\"\r
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\n" ); document.write( "\n" ); document.write( "So the center is (4,3) and the radius is 5 units.\r
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\n" ); document.write( "\n" ); document.write( "Here's the graph:\r
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