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Byju's Answer
Standard X
Mathematics
Nature of Roots Using Discriminant
If the equati...
Question
If the equation
x
2
+
4
x
−
k
=
0
has real and distinct roots, then :
A
k
<
−
4
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B
k
>
−
4
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C
k
≤
−
4
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D
k
≥
−
4
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Solution
The correct option is
B
k
>
−
4
Since the quadratic equation has real and distinct roots, then
D
>
0
∴
b
2
−
4
a
c
>
0
⇒
(
4
)
2
−
4
(
1
)
(
−
k
)
>
0
⇒
16
+
4
k
>
0
⇒
4
k
>
−
16
⇒
k
>
−
4
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