document.write( "Question 91140: Anyone able to figure this one out? Thanks for your assistance.
\n" ); document.write( "What is the equation of the line through points (-3, 2) and (-4, 5)?
\n" ); document.write( "a. y= (-3/2)-7
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\n" ); document.write( "c. y= -3x+7
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Algebra.Com's Answer #66169 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
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Solved by pluggable solver: Finding the Equation of a Line
First lets find the slope through the points (\"-3\",\"2\") and (\"-4\",\"5\")
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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\",\"2\") and (\"x%5B2%5D\",\"y%5B2%5D\") is the second point (\"-4\",\"5\"))
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\n" ); document.write( " \"m=%285-2%29%2F%28-4--3%29\" Plug in \"y%5B2%5D=5\",\"y%5B1%5D=2\",\"x%5B2%5D=-4\",\"x%5B1%5D=-3\" (these are the coordinates of given points)
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\n" ); document.write( " \"m=+3%2F-1\" Subtract the terms in the numerator \"5-2\" to get \"3\". Subtract the terms in the denominator \"-4--3\" to get \"-1\"
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\n" ); document.write( " \"m=-3\" Reduce
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\n" ); document.write( " So the slope is
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\n" ); document.write( " \"m=-3\"
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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-2=%28-3%29%28x--3%29\" Plug in \"m=-3\", \"x%5B1%5D=-3\", and \"y%5B1%5D=2\" (these values are given)
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\n" ); document.write( " \"y-2=%28-3%29%28x%2B3%29\" Rewrite \"x--3\" as \"x%2B3\"
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\n" ); document.write( " \"y-2=-3x%2B%28-3%29%283%29\" Distribute \"-3\"
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\n" ); document.write( " \"y-2=-3x-9\" Multiply \"-3\" and \"3\" to get \"-9%2F1\". Now reduce \"-9%2F1\" to get \"-9\"
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\n" ); document.write( " \"y=-3x-9%2B2\" Add \"2\" to both sides to isolate y
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\n" ); document.write( " \"y=-3x-7\" Combine like terms \"-9\" and \"2\" to get \"-7\"
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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\",\"2\") and (\"-4\",\"5\") is:\"y=-3x-7\"
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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\" and the y-intercept is \"b=-7\"
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\n" ); document.write( " Notice if we graph the equation \"y=-3x-7\" and plot the points (\"-3\",\"2\") and (\"-4\",\"5\"), we get this: (note: if you need help with graphing, check out this solver)
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\n" ); document.write( " Graph of \"y=-3x-7\" through the points (\"-3\",\"2\") and (\"-4\",\"5\")
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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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