document.write( "Question 111347: what is an equation in slope intercept-form for a line passing through(3,4)And (5,8)? \n" ); document.write( "
Algebra.Com's Answer #81195 by jim_thompson5910(35256)\"\" \"About 
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Solved by pluggable solver: Finding the Equation of a Line
First lets find the slope through the points (\"3\",\"4\") and (\"5\",\"8\")
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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 (\"3\",\"4\") and (\"x%5B2%5D\",\"y%5B2%5D\") is the second point (\"5\",\"8\"))
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\n" ); document.write( " \"m=%288-4%29%2F%285-3%29\" Plug in \"y%5B2%5D=8\",\"y%5B1%5D=4\",\"x%5B2%5D=5\",\"x%5B1%5D=3\" (these are the coordinates of given points)
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\n" ); document.write( " \"m=+4%2F2\" Subtract the terms in the numerator \"8-4\" to get \"4\". Subtract the terms in the denominator \"5-3\" to get \"2\"
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\n" ); document.write( " \"m=2\" Reduce
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\n" ); document.write( " So the slope is
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\n" ); document.write( " \"m=2\"
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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-4=%282%29%28x-3%29\" Plug in \"m=2\", \"x%5B1%5D=3\", and \"y%5B1%5D=4\" (these values are given)
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\n" ); document.write( " \"y-4=2x%2B%282%29%28-3%29\" Distribute \"2\"
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\n" ); document.write( " \"y-4=2x-6\" Multiply \"2\" and \"-3\" to get \"-6%2F1\". Now reduce \"-6%2F1\" to get \"-6\"
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\n" ); document.write( " \"y=2x-6%2B4\" Add \"4\" to both sides to isolate y
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\n" ); document.write( " \"y=2x-2\" Combine like terms \"-6\" and \"4\" to get \"-2\"
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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 (\"3\",\"4\") and (\"5\",\"8\") is:\"y=2x-2\"
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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=2\" and the y-intercept is \"b=-2\"
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\n" ); document.write( " Notice if we graph the equation \"y=2x-2\" and plot the points (\"3\",\"4\") and (\"5\",\"8\"), we get this: (note: if you need help with graphing, check out this solver)
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\n" ); document.write( " Graph of \"y=2x-2\" through the points (\"3\",\"4\") and (\"5\",\"8\")
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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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