They can be represented by a two by two matrix with top row x negative y and bottom row y x.  Holomorphic functions take these numbers as inputs.
These numbers are the input to a M?bius transformation, and Gaussian integers are this sort of number.  They can be represented by a two by two matrix with top row x negative y and bottom row y x.  Holomorphic functions take these numbers as inputs. Phasors are another way to represent them, and they are extended by quaternions.  For a given one of these numbers, flipping the sign of the second component in their standard representation yields its conjugate.  If a quadratic polynomial has a negative discriminant, then its roots are of this type.  For 10 points, name these numbers that have real and imaginary components.
These numbers are the input to a M?bius transformation, and Gaussian integers are this sort of number.  
complex number