a)Show that the points representing the complex numbers7 + 9i, -3 + 7i and 3 +3i form a right angled triangle on the Argand diagram.

b) if w = a + ib and z = x + iy, where a,b,x and y are real numbers, such that w=z / 1 +iz, show that a =x / x^2 +(y-1)^2 and b = -{x^2+y^2 -y / x^2 + (y-1)^2}