document.write( "Question 86175: find the slope and the y-intercept of the line whose equation is 2x+3y=12\r
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Algebra.Com's Answer #62264 by jim_thompson5910(35256)\"\" \"About 
You can put this solution on YOUR website!
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Solved by pluggable solver: Converting Linear Equations in Standard form to Slope-Intercept Form (and vice versa)
Convert from standard form (Ax+By = C) to slope-intercept form (y = mx+b)


\"2x%2B3y=12\" Start with the given equation


\"2x%2B3y-2x=12-2x\" Subtract 2x from both sides


\"3y=-2x%2B12\" Simplify


\"%283y%29%2F%283%29=%28-2x%2B12%29%2F%283%29\" Divide both sides by 3 to isolate y


\"y+=+%28-2x%29%2F%283%29%2B%2812%29%2F%283%29\" Break up the fraction on the right hand side


\"y+=+%28-2%2F3%29x%2B4\" Reduce and simplify


The original equation \"2x%2B3y=12\" (standard form) is equivalent to \"y+=+%28-2%2F3%29x%2B4\" (slope-intercept form)


The equation \"y+=+%28-2%2F3%29x%2B4\" is in the form \"y=mx%2Bb\" where \"m=-2%2F3\" is the slope and \"b=4\" is the y intercept.



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Solved by pluggable solver: Finding the Equation of a Line
First lets find the slope through the points (\"1\",\"-3\") and (\"-2\",\"6\")
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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 (\"1\",\"-3\") and (\"x%5B2%5D\",\"y%5B2%5D\") is the second point (\"-2\",\"6\"))
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\n" ); document.write( " \"m=%286--3%29%2F%28-2-1%29\" Plug in \"y%5B2%5D=6\",\"y%5B1%5D=-3\",\"x%5B2%5D=-2\",\"x%5B1%5D=1\" (these are the coordinates of given points)
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\n" ); document.write( " \"m=+9%2F-3\" Subtract the terms in the numerator \"6--3\" to get \"9\". Subtract the terms in the denominator \"-2-1\" to get \"-3\"
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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--3=%28-3%29%28x-1%29\" Plug in \"m=-3\", \"x%5B1%5D=1\", and \"y%5B1%5D=-3\" (these values are given)
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\n" ); document.write( " \"y%2B3=%28-3%29%28x-1%29\" Rewrite \"y--3\" as \"y%2B3\"
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\n" ); document.write( " \"y%2B3=-3x%2B%28-3%29%28-1%29\" Distribute \"-3\"
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\n" ); document.write( " \"y%2B3=-3x%2B3\" Multiply \"-3\" and \"-1\" to get \"3%2F1\". Now reduce \"3%2F1\" to get \"3\"
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\n" ); document.write( " \"y=-3x%2B3-3\" Subtract \"3\" from both sides to isolate y
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\n" ); document.write( " \"y=-3x%2B0\" Combine like terms \"3\" and \"-3\" to get \"0\"
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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 (\"1\",\"-3\") and (\"-2\",\"6\") is:\"y=-3x%2B0\"
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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=0\"
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\n" ); document.write( " Notice if we graph the equation \"y=-3x%2B0\" and plot the points (\"1\",\"-3\") and (\"-2\",\"6\"), 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%2B0\" through the points (\"1\",\"-3\") and (\"-2\",\"6\")
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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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