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Mathematics
Let α=8-14 i , A = z ∈ C: (α z - barα overline z / z 2-( overline z )2-112 i )=1 and B= z ∈ C :|z+3 i|=4 Then displaystyle∑z ∈ A ∩ B( operatornameRe z- operatornameIm z) is equal to
Q. Let
α
=
8
−
14
i
,
A
=
{
z
∈
C
:
z
2
−
(
z
)
2
−
112
i
α
z
−
α
ˉ
z
​
=
1
}
and
B
=
{
z
∈
C
:
∣
z
+
3
i
∣
=
4
}
Then
z
∈
A
∩
B
∑
​
(
Re
z
−
Im
z
)
is equal to
139
1
JEE Main
JEE Main 2023
Complex Numbers and Quadratic Equations
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Answer:
14
Solution:
α
=
8
−
14
i
z
=
x
+
i
y
a
z
=
(
8
x
+
14
y
)
+
i
(
−
14
x
+
8
y
)
z
+
z
=
2
x
z
−
z
=
2
i
y
Set A:
i
(
4
x
y
−
112
)
2
i
(
−
14
x
+
8
y
)
​
=
1
(
x
−
4
)
(
y
+
7
)
=
0
x
=
4
 orÂ
y
=
−
7
Set B:
x
2
+
(
y
+
3
)
2
=
16
when
x
=
4
y
=
−
3
when
y
=
−
7
x
=
0
∴
A
∩
B
=
{
4
−
3
i
,
0
−
7
i
}
So,
z
∈
A
∩
B
∑
​
(
Rez
−
Im
z
)
=
4
−
(
−
3
)
+
(
0
−
(
−
7
))
=
14