Maths Question! (complex numbers)

[imanmalik]

P is a point in an argand diagram corresponding to a complex number z which satisfies |4+z| - |4-z| = 6. Prove that |4+z|^2 - |4-z|^2 ≧ 48 and deduce that Re z ≧ 3.

 

[Khan_971]

Solved.