document.write( "Question 217410: Write an equation in slope-intercept form that passes through (4, 9) and (5, 12) \n" ); document.write( "
Algebra.Com's Answer #163944 by drj(1380)\"\" \"About 
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Write an equation in slope-intercept form that passes through (4, 9) and (5, 12)\r
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\n" ); document.write( "\n" ); document.write( "Step 1. We need to find an equation in slope intercept form given as y=mx+b where m is the slope and b is the y-intercept at point (0,b).\r
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\n" ); document.write( "\n" ); document.write( "Step 2. The slope of the line m is given as\r
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\n" ); document.write( "\n" ); document.write( "\"+m=%28y2-y1%29%2F%28x2-x1%29\"\r
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\n" ); document.write( "\n" ); document.write( "where for our example is x1=4, y1=9, x2=5 and y2=12 (think of \"slope=rise%2Frun\"). You can choose the points the other way around but be consistent with the x and y coordinates. You will get the same result.\r
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\n" ); document.write( "\n" ); document.write( "Step 3. Substituting the above values in the slope equation gives\r
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\n" ); document.write( "\n" ); document.write( "\"m=%2812-9%29%2F%285-4%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"m=3%2F1=3\"\r
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\n" ); document.write( "\n" ); document.write( "Step 4. The slope is calculated as \"3\" or \"m=3\".\r
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\n" ); document.write( "\n" ); document.write( "Step 5. Now use the slope equation of step 1 and choose one of the given points. I'll choose point (4,9). Letting y=y2 and x=x2 and substituting m=60 in the slope equation given as,\r
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\n" ); document.write( "\n" ); document.write( "\"+m=%28y2-y1%29%2F%28x2-x1%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"+3=%28y-9%29%2F%28x-4%29\"\r
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\n" ); document.write( "\n" ); document.write( "Step 6. Multiply both sides of equation by (x-4) to get rid of denomination found on the right side of the equation\r
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\n" ); document.write( "\n" ); document.write( "\"+3%28x-4%29=%28x-4%29%28y-9%29%2F%28x-4%29\"\r
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\n" ); document.write( "\n" ); document.write( "\"+3x-12=%28y-9%29\"\r
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\n" ); document.write( "\n" ); document.write( "Step 7. Now simplify and put the above equation into slope-intercept form.\r
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\n" ); document.write( "\n" ); document.write( "\"3x-12=y-9\"\r
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\n" ); document.write( "\n" ); document.write( "Add 9 to both sides of the equation\r
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\n" ); document.write( "\n" ); document.write( "\"3x-12%2B9=y-9%2B9\"\r
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\n" ); document.write( "\n" ); document.write( "\"3x-3=y\"\r
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\n" ); document.write( "\n" ); document.write( "ANSWER in slope-intercept form is \"y=3x-3\" where slope m=3 band y-intercept=-3\r
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\n" ); document.write( "\n" ); document.write( "Step 8. See if the other point (5,12) or x=5 and y=12 satisfies this equation\r
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\n" ); document.write( "\n" ); document.write( "\"y=3x-3\"\r
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\n" ); document.write( "\n" ); document.write( "\"12=3%2A5-3=12\" So the other point satisfies this equation and lies on the line.\r
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\n" ); document.write( "\n" ); document.write( "In other words, you can use the other point to check your work.\r
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\n" ); document.write( "\n" ); document.write( "Note: above equation can be also be transform into standard form as\r
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\n" ); document.write( "\n" ); document.write( "\"3x-y=3\"\r
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\n" ); document.write( "\n" ); document.write( "See graph below to check the above steps. Note the slope and y-intercept as well as the x-intercept.\r
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\n" ); document.write( "\n" ); document.write( "\"graph%28600%2C600%2C-15%2C15%2C-10%2C10%2C3x-3%29\"\r
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\n" ); document.write( "\n" ); document.write( "I hope the above steps were helpful. \r
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\n" ); document.write( "And good luck in your studies!\r
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\n" ); document.write( "\n" ); document.write( "For free Step-By-Step Videos on Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra or for Trigonometry visit http://www.FreedomUniversity.TV/courses/Trigonometry.\r
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\n" ); document.write( "\n" ); document.write( "Respectfully,
\n" ); document.write( "Dr J
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