{z : |z - 1| = 2} ..... The distance of z from 1 is always equal to 2. Geometrically then z lies on a circle of radius 2 and centre at z = 1.

{z : Re z less then or equal to 0} ..... You have the left half of the complex plane (the part to the left of the Im(z) axis).

Put the two together and look for the overlap ......