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Byju's Answer
Standard VIII
Mathematics
Expansion of (x+y)^2
fx=x4+3x2-6x-...
Question
f
(
x
)
=
x
4
+
3
x
2
−
6
x
−
2
then the coefficient of
x
3
in
f
(
x
+
1
)
is
A
24
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B
-24
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C
4
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D
-4
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Solution
The correct option is
C
4
Given:
f
(
x
)
=
x
4
+
3
x
2
−
6
x
−
2
To find the coefficient of
x
3
in
f
(
x
+
1
)
Sol:
f
(
x
)
=
x
4
+
3
x
2
−
6
x
−
2
f
(
x
+
1
)
=
(
x
+
1
)
4
+
3
(
x
+
1
)
2
−
6
(
x
+
1
)
−
2
⟹
f
(
x
+
1
)
=
x
4
+
4
x
3
+
6
x
2
+
4
x
+
1
+
3
(
x
2
+
x
+
1
)
−
6
x
−
6
−
2
As
(
a
+
b
)
4
=
a
4
+
4
a
3
b
+
6
a
2
b
2
+
4
a
b
3
+
b
4
Hence the coefficient of
x
3
in
f
(
x
+
1
)
is 4
Suggest Corrections
0
Similar questions
Q.
If
f
(
x
)
=
1
+
x
2
−
x
3
+
.
.
.
−
x
15
+
x
16
−
x
17
, then the coefficient of
x
2
in
f
(
x
−
1
)
is
Q.
f(x) = x
4
− 3x
2
+ 4, g(x) = x − 2