x³+1/x³=9 Find x-1/x
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Answers
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0
Step-by-step explanation:
The correct option is A
702
Given that
x
+
1
x
=
9
Taking cube on both sides, we have
(
x
+
1
x
)
3
=
(
9
)
3
⇒
x
3
+
1
x
3
+
(
3
)
(
x
)
(
1
x
)
(
x
+
1
x
)
=
729
⇒
x
3
+
1
x
3
+
(
3
)
(
9
)
=
(
729
)
( Substituting
x
+
1
x
=
9
)
⇒
x
3
+
1
x
3
=
729
−
27
=
702
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