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Byju's Answer
Standard VII
Mathematics
Expression Formation
If x=2, y=-...
Question
If
x
=
2
,
y
=
−
1
,
z
=
4
; find the value of the following expression
x
2
+
y
2
+
z
2
−
x
y
−
y
z
−
z
x
.
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Solution
For
x
=
2
,
y
=
−
1
,
z
=
4
x
2
+
y
2
+
z
2
−
x
y
−
y
z
−
z
x
=
(
2
)
2
+
(
−
1
)
2
+
4
2
−
(
2
)
(
−
1
)
−
(
−
1
)
(
4
)
−
2
(
4
)
=
4
+
1
+
16
+
2
+
4
−
8
=
19
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1
Similar questions
Q.
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Q.
Show that
x
2
+
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+
z
2
−
x
y
−
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−
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=
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[
(
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)
2
+
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]
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If
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