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Question
Show that the following points are collinear:
A(5,1), B(1, -1) and C(11, 4)
Solution
`"Let" A(x_1=5,y_1=1), B(x_2=1,y_2=-1) and C(x_3=11,y_3=4)`be the given points.
Now `x_1 (y_2-y_3)+x_2(y_3-y_1)+x_3(y_1-y_2)`
=5(-1-4)+1(4-1)+11(1+1)
=-25+3+22
=0
Hence, the given points are collinear.
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