Question

The necessary and sufficient condition for the points Z1,Z2,Z3, to be collinear is that
1 )Z3-Z2/Z2-Z1 is purely real
2)Z3+Z2/Z2+Z1 is purely real
3)Z2+Z1/Z3+Z2 is purely imaginary
4)Z2-Z1/Z3-Z2 is purely imaginary​

Answer 1

Answer:

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