Answer
Ans. $|Z_1-Z_2|=\sqrt {(x_2-x_1) ^2+(y_2-y_1)^2}$
Work Step by Step
Given:$z_1=x_1+iy_1$,$z_2=x_2+iy_2$
=
$z_1-z_2=(x_1+iy_1)-(x_2+iy_2)$
=$|Z_1-Z_2|=\sqrt {(x_2-x_1) ^2+(y_2-y_1)^2}$
the distance between Z1 and Z2 are shown on Argand diagram.
