If the three points A, B and C with the coordinates (4, 2), (3, 1) and (2, a) respectively lie on a line, what is the value of a?
Options.
A) 0	B) 1	C) 2	D) 3	E) 4
The Line will have the same slope irrespective of which two points are taken into account   i.e. Slope of Line using Points (4, 2), (3, 1) = Slope of Line using Points (4, 2), (2, a)   CONCEPT: Slope between two points (a, b) and (c, d) = (d-b)/(c-a)   i.e. (1-2)/(3-4) = (a-2)/(2-4)   i.e. (a-2) = -2   i.e. a = 0   0nswer: option 0
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If the three points A, B and C with the coordinates (4, 2), (3, 1) and (2, a) respectively lie on a line, what is the value of a?