document.write( "Question 127909: Write an equation for the line with x-intercept 4 and y-intercept -3. \n" ); document.write( "
Algebra.Com's Answer #93684 by jim_thompson5910(35256)\"\" \"About 
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Since the x-intercept is 4 and the y-intercept is -3, this means that the line goes through the points (4,0) and (0,-3).\r
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\n" ); document.write( "\n" ); document.write( "First lets find the slope through the points (\"4\",\"0\") and (\"0\",\"-3\")\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 (\"4\",\"0\") and is the second point (\"0\",\"-3\"))\r
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\n" ); document.write( "\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)\r
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\n" ); document.write( "\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\"\r
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\n" ); document.write( "\n" ); document.write( "\"m=3%2F4\" Reduce\r
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\n" ); document.write( "\n" ); document.write( "So the slope is\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-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)\r
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\n" ); document.write( "\n" ); document.write( "\"y-0=%283%2F4%29x%2B%283%2F4%29%28-4%29\" Distribute \"3%2F4\"\r
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\n" ); document.write( "\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\"\r
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\n" ); document.write( "\n" ); document.write( "\"y=%283%2F4%29x-3%2B0\" Add \"0\" to both sides to isolate y\r
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\n" ); document.write( "\n" ); document.write( "\"y=%283%2F4%29x-3\" Combine like terms \"-3\" and \"0\" to get \"-3\" \r
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\n" ); document.write( "\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\"\r
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\n" ); document.write( "\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\"\r
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\n" ); document.write( "\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)\r
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\n" ); document.write( "\n" ); document.write( " Graph of \"y=%283%2F4%29x-3\" through the points (\"4\",\"0\") and (\"0\",\"-3\")\r
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\n" ); document.write( "\n" ); document.write( "Notice how the two points lie on the line. This graphically verifies our answer.
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