document.write( "Question 82485: Find the equation of the line with an x-intercept of 4 and a y-intercept of -3. \n" ); document.write( "
Algebra.Com's Answer #59078 by jim_thompson5910(35256)\"\" \"About 
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Since we know the intercepts, we know 2 points on the line which are (4,0) and (0,-3)\r
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Solved by pluggable solver: Finding the Equation of a Line
First lets find the slope through the points (\"4\",\"0\") and (\"0\",\"-3\")
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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 (\"4\",\"0\") and (\"x%5B2%5D\",\"y%5B2%5D\") is the second point (\"0\",\"-3\"))
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\n" ); document.write( " \"m=%28-3-0%29%2F%280-4%29\" Plug in \"y%5B2%5D=-3\",\"y%5B1%5D=0\",\"x%5B2%5D=0\",\"x%5B1%5D=4\" (these are the coordinates of given points)
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\n" ); document.write( " \"m=+-3%2F-4\" Subtract the terms in the numerator \"-3-0\" to get \"-3\". Subtract the terms in the denominator \"0-4\" to get \"-4\"
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\n" ); document.write( " \"m=3%2F4\" Reduce
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\n" ); document.write( " So the slope is
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\n" ); document.write( " \"m=3%2F4\"
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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=%283%2F4%29%28x-4%29\" Plug in \"m=3%2F4\", \"x%5B1%5D=4\", and \"y%5B1%5D=0\" (these values are given)
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\n" ); document.write( " \"y-0=%283%2F4%29x%2B%283%2F4%29%28-4%29\" Distribute \"3%2F4\"
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\n" ); document.write( " \"y-0=%283%2F4%29x-3\" Multiply \"3%2F4\" and \"-4\" to get \"-12%2F4\". Now reduce \"-12%2F4\" to get \"-3\"
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\n" ); document.write( " \"y=%283%2F4%29x-3%2B0\" Add \"0\" to both sides to isolate y
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\n" ); document.write( " \"y=%283%2F4%29x-3\" Combine like terms \"-3\" and \"0\" to get \"-3\"
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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 (\"4\",\"0\") and (\"0\",\"-3\") is:\"y=%283%2F4%29x-3\"
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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=3%2F4\" and the y-intercept is \"b=-3\"
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\n" ); document.write( " Notice if we graph the equation \"y=%283%2F4%29x-3\" and plot the points (\"4\",\"0\") and (\"0\",\"-3\"), we get this: (note: if you need help with graphing, check out this solver)
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\n" ); document.write( " Graph of \"y=%283%2F4%29x-3\" through the points (\"4\",\"0\") and (\"0\",\"-3\")
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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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