z4−4z3+17z2−16z+52=0
z1=2i → z2=−2i
(z4−4z3+17z2−16z+52) : [(z−2i)(z+2i)=(z4−4z3+17z2−16z+52) : [z2−4i2]=(z4−4z3+17z2−16z+52) : [z2+4]
Polynomdivision
(z4−4z3+17z2−16z+52) : (z2+4)=z2−4z+13
−(z4+4z2)
.........................
−4z3+13z2−16z+52
−(−4z3−16z)
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13z2+52
−(13z2+52)
..............................................
0
z2−4z+13=0
z2−4z=−13
z2−4z+(24)2=−13+(24)2
(z−2)2=−13+4=−9=9i2∣±
1.)
z−2=3i
z3=2+3i
2.)
z−2=−3i
z4=2−3i