To find the sum of the squared moduli of the roots of the quadratic equation z2+4z−(1+12i)=0, we can complete the square for z:
(z+2)2−4−1−12i=0
(z+2)2=5+12i
Let w=z+2=x+iy, where x,y∈R. Then:
(x+iy)2=5+12i
(x2−y2)+2ixy=5+12i
Equating the real and imaginary parts:
- x2−y2=5
- 2xy=12⟹xy=6
Using the identity (x2+y2)2=(x2−y2)2+(2xy)2, we get:
(x2+y2)2=52+122=25+144=169
x2+y2=13
Adding x2−y2=5 and x2+y2=13:
2x2=18⟹x2=9⟹x=±3
Subtracting x2−y2=5 from x2+y2=13:
2y2=8⟹y2=4⟹y=±2
Since xy=6>0, x and y must have the same sign. Therefore, w=z+2=±(3+2i).
This gives us the two roots z1 and z2:
z1=(3+2i)−2=1+2i
z2=(−3−2i)−2=−5−2i
Now, calculating the squared moduli of the roots:
∣z1∣2=12+22=1+4=5
∣z2∣2=(−5)2+(−2)2=25+4=29
Sum of squared moduli:
∣z1∣2+∣z2∣2=5+29=34
Thus, the correct option is D.