document.write( "Question 458436: Given the linear equation y = 3/4x-2, find the y-coordinates of the points (-8, ), (-4, ), and (4, ). Please show all of your work. Plot those points and graph the linear equation. \n" ); document.write( "
Algebra.Com's Answer #314511 by MathLover1(20850)\"\" \"About 
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\n" ); document.write( "\n" ); document.write( "Given the linear equation \"y+=+%283%2F4%29x-2\", find the \"y-coordinates\" of the points \r
\n" ); document.write( "\n" ); document.write( "\"x=-8\"\r
\n" ); document.write( "\n" ); document.write( "\"y+=+%283%2F4%29%28-8%29-2=-24%2F4-2=-6-2=-8\"\r
\n" ); document.write( "\n" ); document.write( "\"x=-4\"\r
\n" ); document.write( "\n" ); document.write( "\"y+=+%283%2F4%29%28-4%29-2=-12%2F4-2=-3-2=-5\"\r
\n" ); document.write( "\n" ); document.write( "\"x=4\"\r
\n" ); document.write( "\n" ); document.write( "\"y+=+%283%2F4%29%284%29-2=12%2F4-2=3-2=1\"\r
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\n" ); document.write( "\n" ); document.write( "so, the \"y-coordinates\" are\r
\n" ); document.write( "\n" ); document.write( "(-8, -8 ), (-4, -5 ), and (4,1 )\r
\n" ); document.write( "\n" ); document.write( "check if these \"3\" points lie in a same line\r
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Solved by pluggable solver: To determine if 3 points lie in a line
The 3 points lie on a same plane. For all points to lie on a line they should satisfy the equation of a line. Hence any two points taken on a line should calculate to the same slope of a line.
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\n" ); document.write( " In order to prove the 3 points to lie on a line, as there exists a unique line containing three points and every line has a unique slope.
\n" ); document.write( " Hence it will be sufficient to prove that the slope calculated taking 2 points at a time should be equal.
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\n" ); document.write( " Slope of line taking points (X1,Y1) and (X2,Y2) is
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\n" ); document.write( " \"slope+=+%28Y2-Y1%29%2F%28X2-X1%29\"
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\n" ); document.write( " \"slope+=+%28%28-5--8%29%2F%28-4--8%29%29+=+0.75\" ........................(1)
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\n" ); document.write( " Slope of line taking points (X3,Y3) and (X1,Y1) is
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\n" ); document.write( " \"slope+=+%28Y3-Y1%29%2F%28X3-X1%29\"
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\n" ); document.write( " \"slope+=+%28%281--8%29%2F%284--8%29%29+=+0.75\" ........................(2)
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\n" ); document.write( " From conditions (1) and (2)
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\n" ); document.write( " The slopes are equal hence the 3 points can lie on same line.
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\n" ); document.write( " If the slope calculated from points (X2,Y2) and (X3,Y3) comes out to be same then it is confirmed that the 3 points lie on a same line.
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\n" ); document.write( " \"slope+=+%28Y3-Y2%29%2F%28X3-X2%29\"
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\n" ); document.write( " \"slope+=+%28%281--5%29%2F%284--4%29%29+=+0.75\" ........................(3)
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\n" ); document.write( " From (1),(2) and (3)
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\n" ); document.write( " Hence, It is proved that the 3 points lie on same line.
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\n" ); document.write( " To read more on equations of a line refer to articles on wikipedia
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\n" ); document.write( "\n" ); document.write( "let's see the graph:\r
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\n" ); document.write( "\n" ); document.write( "\"+graph%28+500%2C+500%2C+-10%2C+10%2C+-10%2C+10%2C+%283%2F4%29x-2%29+\"\r
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