document.write( "Question 102093: give an equation for the line whose x-intercept is 5 and whose y-intercept is -4 \n" ); document.write( "
Algebra.Com's Answer #74381 by edjones(8007)\"\" \"About 
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(5,0)(0,-4)
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Solved by pluggable solver: Finding the Equation of a Line
First lets find the slope through the points (\"5\",\"0\") and (\"0\",\"-4\")
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\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: (\"x%5B1%5D\",\"y%5B1%5D\") is the first point (\"5\",\"0\") and (\"x%5B2%5D\",\"y%5B2%5D\") is the second point (\"0\",\"-4\"))
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\n" ); document.write( " \"m=%28-4-0%29%2F%280-5%29\" Plug in \"y%5B2%5D=-4\",\"y%5B1%5D=0\",\"x%5B2%5D=0\",\"x%5B1%5D=5\" (these are the coordinates of given points)
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\n" ); document.write( " \"m=+-4%2F-5\" Subtract the terms in the numerator \"-4-0\" to get \"-4\". Subtract the terms in the denominator \"0-5\" to get \"-5\"
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\n" ); document.write( " \"m=4%2F5\" Reduce
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\n" ); document.write( " So the slope is
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\n" ); document.write( " \"m=4%2F5\"
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\n" ); document.write( "Now let's use the point-slope formula to find the equation of the line:
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\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 (\"x%5B1%5D\",\"y%5B1%5D\") is one of the given points
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\n" ); document.write( " So lets use the Point-Slope Formula to find the equation of the line
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\n" ); document.write( " \"y-0=%284%2F5%29%28x-5%29\" Plug in \"m=4%2F5\", \"x%5B1%5D=5\", and \"y%5B1%5D=0\" (these values are given)
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\n" ); document.write( " \"y-0=%284%2F5%29x%2B%284%2F5%29%28-5%29\" Distribute \"4%2F5\"
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\n" ); document.write( " \"y-0=%284%2F5%29x-4\" Multiply \"4%2F5\" and \"-5\" to get \"-20%2F5\". Now reduce \"-20%2F5\" to get \"-4\"
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\n" ); document.write( " \"y=%284%2F5%29x-4%2B0\" Add \"0\" to both sides to isolate y
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\n" ); document.write( " \"y=%284%2F5%29x-4\" Combine like terms \"-4\" and \"0\" to get \"-4\"
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\n" ); document.write( " Answer:
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\n" ); document.write( " So the equation of the line which goes through the points (\"5\",\"0\") and (\"0\",\"-4\") is:\"y=%284%2F5%29x-4\"
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\n" ); document.write( " The equation is now in \"y=mx%2Bb\" form (which is slope-intercept form) where the slope is \"m=4%2F5\" and the y-intercept is \"b=-4\"
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\n" ); document.write( " Notice if we graph the equation \"y=%284%2F5%29x-4\" and plot the points (\"5\",\"0\") and (\"0\",\"-4\"), we get this: (note: if you need help with graphing, check out this solver)
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\n" ); document.write( " Graph of \"y=%284%2F5%29x-4\" through the points (\"5\",\"0\") and (\"0\",\"-4\")
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\n" ); document.write( " Notice how the two points lie on the line. This graphically verifies our answer.
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