Letters z and w are often used as complex variables, where z = x + yi, w = u + vi, and x,...

Letters z and w are often used as complex variables, where z = x + yi, w = u + vi, and x, y, u, v are real numbers. The conjugates of z and w, denoted by and , respectively, are given by and. Express the property of conjugates verbally and then prove the property.

z −   is a real number.