document.write( "Question 98369: Consider the line y=7x+8. \r
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\n" ); document.write( "\n" ); document.write( "Find the equation of the line that is parallel to this line and passes through the point(5,9).\r
\n" ); document.write( "\n" ); document.write( "Find the equation of the line that is perpendicular to this line and passes through the point (5,9).\r
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Algebra.Com's Answer #71577 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
\"Find the equation of the line that is parallel to this line and passes through the point(5,9).\"\r
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Solved by pluggable solver: Finding the Equation of a Line Parallel or Perpendicular to a Given Line

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\n" ); document.write( " Since any two parallel lines have the same slope we know the slope of the unknown line is \"7\" (its from the slope of \"y=7%2Ax%2B8\" which is also \"7\").\n" ); document.write( "Also since the unknown line goes through (5,9), we can find the equation by plugging in this info into the point-slope formula
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\n" ); document.write( " Point-Slope Formula:
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\n" ); document.write( " \"y-y%5B1%5D=m%28x-x%5B1%5D%29\" where m is the slope and (\"x%5B1%5D\",\"y%5B1%5D\") is the given point
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\n" ); document.write( " \"y-9=7%2A%28x-5%29\" Plug in \"m=7\", \"x%5B1%5D=5\", and \"y%5B1%5D=9\"
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\n" ); document.write( " \"y-9=7%2Ax-%287%29%285%29\" Distribute \"7\"
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\n" ); document.write( " \"y-9=7%2Ax-35\" Multiply
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\n" ); document.write( " \"y=7%2Ax-35%2B9\"Add \"9\" to both sides to isolate y
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\n" ); document.write( " \"y=7%2Ax-26\" Combine like terms
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\n" ); document.write( " So the equation of the line that is parallel to \"y=7%2Ax%2B8\" and goes through (\"5\",\"9\") is \"y=7%2Ax-26\"
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\n" ); document.write( " So here are the graphs of the equations \"y=7%2Ax%2B8\" and \"y=7%2Ax-26\"
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\n" ); document.write( " graph of the given equation \"y=7%2Ax%2B8\" (red) and graph of the line \"y=7%2Ax-26\"(green) that is parallel to the given graph and goes through (\"5\",\"9\")
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\n" ); document.write( "\n" ); document.write( "\"Find the equation of the line that is perpendicular to this line and passes through the point(5,9).\"\r
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Solved by pluggable solver: Finding the Equation of a Line Parallel or Perpendicular to a Given Line

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\n" ); document.write( " Remember, any two perpendicular lines are negative reciprocals of each other. So if you're given the slope of \"7\", you can find the perpendicular slope by this formula:
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\n" ); document.write( " \"m%5Bp%5D=-1%2Fm\" where \"m%5Bp%5D\" is the perpendicular slope
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\n" ); document.write( " \"m%5Bp%5D=-1%2F%287%2F1%29\" So plug in the given slope to find the perpendicular slope
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\n" ); document.write( " \"m%5Bp%5D=%28-1%2F1%29%281%2F7%29\" When you divide fractions, you multiply the first fraction (which is really \"1%2F1\") by the reciprocal of the second
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\n" ); document.write( " \"m%5Bp%5D=-1%2F7\" Multiply the fractions.
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\n" ); document.write( " So the perpendicular slope is \"-1%2F7\"
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\n" ); document.write( " So now we know the slope of the unknown line is \"-1%2F7\" (its the negative reciprocal of \"7\" from the line \"y=7%2Ax%2B8\").\n" ); document.write( "Also since the unknown line goes through (5,9), we can find the equation by plugging in this info into the point-slope formula
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\n" ); document.write( " Point-Slope Formula:
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\n" ); document.write( " \"y-y%5B1%5D=m%28x-x%5B1%5D%29\" where m is the slope and (\"x%5B1%5D\",\"y%5B1%5D\") is the given point
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\n" ); document.write( " \"y-9=%28-1%2F7%29%2A%28x-5%29\" Plug in \"m=-1%2F7\", \"x%5B1%5D=5\", and \"y%5B1%5D=9\"
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\n" ); document.write( " \"y-9=%28-1%2F7%29%2Ax%2B%281%2F7%29%285%29\" Distribute \"-1%2F7\"
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\n" ); document.write( " \"y-9=%28-1%2F7%29%2Ax%2B5%2F7\" Multiply
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\n" ); document.write( " \"y=%28-1%2F7%29%2Ax%2B5%2F7%2B9\"Add \"9\" to both sides to isolate y
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\n" ); document.write( " \"y=%28-1%2F7%29%2Ax%2B5%2F7%2B63%2F7\" Make into equivalent fractions with equal denominators
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\n" ); document.write( " \"y=%28-1%2F7%29%2Ax%2B68%2F7\" Combine the fractions
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\n" ); document.write( " \"y=%28-1%2F7%29%2Ax%2B68%2F7\" Reduce any fractions
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\n" ); document.write( " So the equation of the line that is perpendicular to \"y=7%2Ax%2B8\" and goes through (\"5\",\"9\") is \"y=%28-1%2F7%29%2Ax%2B68%2F7\"
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\n" ); document.write( " So here are the graphs of the equations \"y=7%2Ax%2B8\" and \"y=%28-1%2F7%29%2Ax%2B68%2F7\"
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\n" ); document.write( " graph of the given equation \"y=7%2Ax%2B8\" (red) and graph of the line \"y=%28-1%2F7%29%2Ax%2B68%2F7\"(green) that is perpendicular to the given graph and goes through (\"5\",\"9\")
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