Algebra.Com's Answer #409227 by MathLover1(20850)  You can put this solution on YOUR website! If , , , then the graph of the function contains the point ( , ),( , ), and ( , ). \r \n" );
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document.write( "Use the two point form of an equation of a straight line and the points ( , ),( , ): \r \n" );
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document.write( " where (x1,y1)and (x2,y2) are the coordinates of the given points. \r \n" );
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document.write( "here is a proof that all three of given points lie on this line\r \n" );
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document.write( " Solved by pluggable solver: To determine if 3 points lie in a line | \n" );
document.write( " 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. \n" );
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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. \n" );
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document.write( " Slope of line taking points (X1,Y1) and (X2,Y2) is \n" );
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document.write( " ........................(1) \n" );
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document.write( " Slope of line taking points (X3,Y3) and (X1,Y1) is \n" );
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document.write( " ........................(2) \n" );
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document.write( " From conditions (1) and (2) \n" );
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document.write( " The slopes are equal hence the 3 points can lie on same line. \n" );
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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. \n" );
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document.write( " ........................(3) \n" );
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document.write( " From (1),(2) and (3) \n" );
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document.write( " Hence, It is proved that the 3 points lie on same line. \n" );
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document.write( " To read more on equations of a line refer to articles on wikipedia \n" );
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