I try to enter answer I thought.

I think the first question should be a^2+b^2+c^2+d^2

But it is not correct.

I use the formula which is abs(z) = sqrt(a^2+b^c)

Besides, I really some explanation about abs(z) in complex number.

For complex numbers z and w, the parallelogram law states that Iz+ w|2 + Iz w|2 = 2 (Izzl2 + IWIZ) or, using quadrances, QMHWHM-M=2@+QML Let's prove the parallelogram law. Suppose z = a + lb and w = c + id . Then Adding, we get aa=xga+gm. Q(z + w) + Q(z w) = I 2(a"2+b'\\2+c/'2+d'\\2) OED