A quadratic eqn with complex coefficients would give a 3-D graph.......... which does not fit into the Argand plane..........
But if U want to make a graph in 2-D, U can picture it by taking it on two planes x-z, and y-z ...
U can do this by breaking the coefficients to pure real and pure imaginary parts........
eg. (a1+ia2)z2+(b1+ib2)z+(c1+ic2)=0
can be written as (a1z2+b1z+c1)+i(a2z2+b2z+c2)=0
Neither of these graphs, truly represents the function, but when U add the two, considering their dimensions, U get the real graph, this cannot be obtained on a plane.
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