document.write( "Question 98508: line Z goes through the point (2, -4) and is perpendicular to the line through (-6,5) and (-3, -2). What is the slope of Z? I don't even know where to start. \n" ); document.write( "
Algebra.Com's Answer #71668 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
Lets find the equation of the line through (-6,5) and (-3, -2)\r
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\n" ); document.write( "\n" ); document.write( "First lets find the slope through the points (\"-6\",\"5\") and (\"-3\",\"-2\")\r
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\n" ); document.write( "\n" ); document.write( "\"m=%28y%5B2%5D-y%5B1%5D%29%2F%28x%5B2%5D-x%5B1%5D%29\" Start with the slope formula (note: is the first point (\"-6\",\"5\") and is the second point (\"-3\",\"-2\"))\r
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\n" ); document.write( "\n" ); document.write( "\"m=%28-2-5%29%2F%28-3--6%29\" Plug in \"y%5B2%5D=-2\",\"y%5B1%5D=5\",\"x%5B2%5D=-3\",\"x%5B1%5D=-6\" (these are the coordinates of given points)\r
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\n" ); document.write( "\n" ); document.write( "\"m=+-7%2F3\" Subtract the terms in the numerator \"-2-5\" to get \"-7\". Subtract the terms in the denominator \"-3--6\" to get \"3\"\r
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\n" ); document.write( "\n" ); document.write( "So the slope is\r
\n" ); document.write( "\n" ); document.write( "\"m=-7%2F3\"\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 line:\r
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\n" ); document.write( "\n" ); document.write( "------Point-Slope Formula------
\n" ); document.write( "\"y-y%5B1%5D=m%28x-x%5B1%5D%29\" where \"m\" is the slope, and is one of the given points\r
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\n" ); document.write( "\n" ); document.write( "So lets use the Point-Slope Formula to find the equation of the line\r
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\n" ); document.write( "\n" ); document.write( "\"y-5=%28-7%2F3%29%28x--6%29\" Plug in \"m=-7%2F3\", \"x%5B1%5D=-6\", and \"y%5B1%5D=5\" (these values are given)\r
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\n" ); document.write( "\n" ); document.write( "\"y-5=%28-7%2F3%29%28x%2B6%29\" Rewrite \"x--6\" as \"x%2B6\"\r
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\n" ); document.write( "\n" ); document.write( "\"y-5=%28-7%2F3%29x%2B%28-7%2F3%29%286%29\" Distribute \"-7%2F3\"\r
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\n" ); document.write( "\n" ); document.write( "\"y-5=%28-7%2F3%29x-14\" Multiply \"-7%2F3\" and \"6\" to get \"-42%2F3\". Now reduce \"-42%2F3\" to get \"-14\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-7%2F3%29x-14%2B5\" Add \"5\" to both sides to isolate y\r
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\n" ); document.write( "\n" ); document.write( "\"y=%28-7%2F3%29x-9\" Combine like terms \"-14\" and \"5\" to get \"-9\" \r
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\n" ); document.write( "\n" ); document.write( "So the equation of the line which goes through the points (\"-6\",\"5\") and (\"-3\",\"-2\") is:\"y=%28-7%2F3%29x-9\"\r
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\n" ); document.write( "\n" ); document.write( "Now let's find the equation of the line perpendicular to \"y=%28-7%2F3%29x-9\" and goes through (2,-4)\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%2F3\", 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%28-7%2F3%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%283%2F-7%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=3%2F7\" Multiply the fractions.
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\n" ); document.write( " So the perpendicular slope is \"3%2F7\"
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\n" ); document.write( " So now we know the slope of the unknown line is \"3%2F7\" (its the negative reciprocal of \"-7%2F3\" from the line \"y=%28-7%2F3%29%2Ax-9\").\n" ); document.write( "Also since the unknown line goes through (2,-4), 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%2B4=%283%2F7%29%2A%28x-2%29\" Plug in \"m=3%2F7\", \"x%5B1%5D=2\", and \"y%5B1%5D=-4\"
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\n" ); document.write( " \"y%2B4=%283%2F7%29%2Ax-%283%2F7%29%282%29\" Distribute \"3%2F7\"
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\n" ); document.write( " \"y%2B4=%283%2F7%29%2Ax-6%2F7\" Multiply
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\n" ); document.write( " \"y=%283%2F7%29%2Ax-6%2F7-4\"Subtract \"-4\" from both sides to isolate y
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\n" ); document.write( " \"y=%283%2F7%29%2Ax-6%2F7-28%2F7\" Make into equivalent fractions with equal denominators
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\n" ); document.write( " \"y=%283%2F7%29%2Ax-34%2F7\" Combine the fractions
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\n" ); document.write( " \"y=%283%2F7%29%2Ax-34%2F7\" Reduce any fractions
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\n" ); document.write( " So the equation of the line that is perpendicular to \"y=%28-7%2F3%29%2Ax-9\" and goes through (\"2\",\"-4\") is \"y=%283%2F7%29%2Ax-34%2F7\"
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\n" ); document.write( " So here are the graphs of the equations \"y=%28-7%2F3%29%2Ax-9\" and \"y=%283%2F7%29%2Ax-34%2F7\"
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\n" ); document.write( " graph of the given equation \"y=%28-7%2F3%29%2Ax-9\" (red) and graph of the line \"y=%283%2F7%29%2Ax-34%2F7\"(green) that is perpendicular to the given graph and goes through (\"2\",\"-4\")
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