document.write( "Question 74619: Write the equation of the line with x-intercept (12, 0) and y-intercept (0, 4). \n" ); document.write( "
Algebra.Com's Answer #53666 by jim_thompson5910(35256)\"\" \"About 
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To find the equation that goes through (12, 0) and (0, 4) we need to find the slope:
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Solved by pluggable solver: Finding the Equation of a Line
First lets find the slope through the points (\"12\",\"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 (\"12\",\"0\") and (\"x%5B2%5D\",\"y%5B2%5D\") is the second point (\"0\",\"4\"))
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\n" ); document.write( " \"m=%284-0%29%2F%280-12%29\" Plug in \"y%5B2%5D=4\",\"y%5B1%5D=0\",\"x%5B2%5D=0\",\"x%5B1%5D=12\" (these are the coordinates of given points)
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\n" ); document.write( " \"m=+4%2F-12\" Subtract the terms in the numerator \"4-0\" to get \"4\". Subtract the terms in the denominator \"0-12\" to get \"-12\"
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\n" ); document.write( " \"m=-1%2F3\" Reduce
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\n" ); document.write( " So the slope is
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\n" ); document.write( " \"m=-1%2F3\"
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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=%28-1%2F3%29%28x-12%29\" Plug in \"m=-1%2F3\", \"x%5B1%5D=12\", and \"y%5B1%5D=0\" (these values are given)
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\n" ); document.write( " \"y-0=%28-1%2F3%29x%2B%28-1%2F3%29%28-12%29\" Distribute \"-1%2F3\"
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\n" ); document.write( " \"y-0=%28-1%2F3%29x%2B4\" Multiply \"-1%2F3\" and \"-12\" to get \"12%2F3\". Now reduce \"12%2F3\" to get \"4\"
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\n" ); document.write( " \"y=%28-1%2F3%29x%2B4%2B0\" Add \"0\" to both sides to isolate y
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\n" ); document.write( " \"y=%28-1%2F3%29x%2B4\" 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 (\"12\",\"0\") and (\"0\",\"4\") is:\"y=%28-1%2F3%29x%2B4\"
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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=-1%2F3\" and the y-intercept is \"b=4\"
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\n" ); document.write( " Notice if we graph the equation \"y=%28-1%2F3%29x%2B4\" and plot the points (\"12\",\"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=%28-1%2F3%29x%2B4\" through the points (\"12\",\"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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\n" ); document.write( "\n" ); document.write( "So the equation is
\n" ); document.write( "\"y=%28-1%2F3%29x%2B4\"
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