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Joint Entrance Examination
Mathematics
Complex Numbers
Question 360
Question 360 of 455
Medium
MCQ
If the cube roots of unity are
1
,
ω
,
ω
2
1,\omega,\omega^2
1
,
ω
,
ω
2
, then the roots of
(
x
−
1
)
3
+
8
=
0
(x-1)^3+8=0
(
x
−
1
)
3
+
8
=
0
are
A
−
1
,
−
1
+
2
ω
,
−
1
−
2
ω
2
-1,-1+2\omega,-1-2\omega^2
−
1
,
−
1
+
2
ω
,
−
1
−
2
ω
2
B
−
1
,
−
1
,
−
1
-1,-1,-1
−
1
,
−
1
,
−
1
C
−
1
,
1
−
2
ω
,
1
−
2
ω
2
-1,1-2\omega,1-2\omega^2
−
1
,
1
−
2
ω
,
1
−
2
ω
2
D
−
1
,
1
+
2
ω
,
1
+
2
ω
2
-1,1+2\omega,1+2\omega^2
−
1
,
1
+
2
ω
,
1
+
2
ω
2
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Official solution
(
x
−
1
)
3
=
−
8
⟹
x
−
1
=
−
2
,
−
2
ω
,
−
2
ω
2
(x-1)^3=-8 \implies x-1=-2,\ -2\omega,\ -2\omega^2
(
x
−
1
)
3
=
−
8
⟹
x
−
1
=
−
2
,
−
2
ω
,
−
2
ω
2
, so
x
=
−
1
,
1
−
2
ω
,
1
−
2
ω
2
.
x=-1,\ 1-2\omega,\ 1-2\omega^2.
x
=
−
1
,
1
−
2
ω
,
1
−
2
ω
2
.
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