1
You visited us
1
times! Enjoying our articles?
Unlock Full Access!
Byju's Answer
Standard VIII
Mathematics
Algebraic Identities
If 2 x + y 3=...
Question
If
2
x
+
y
3
=
12
and
x
y
=
30
,
then
8
x
3
+
y
3
27
=
_
_
_
_
_
_
_
(a) 1008
(b) 168
(c) 106
(d) none of these
Open in App
Solution
Given
:
2
x
+
y
3
=
12
.
.
.
1
x
y
=
30
.
.
.
2
Now
,
2
x
+
y
3
=
12
Taking
cube
on
both
sides
,
we
get
⇒
2
x
+
y
3
3
=
12
3
⇒
2
x
3
+
y
3
3
+
3
2
x
y
3
2
x
+
y
3
=
1728
Using
the
identity
:
a
+
b
3
=
a
3
+
b
3
+
3
a
b
a
+
b
⇒
8
x
3
+
y
3
27
+
2
x
y
2
x
+
y
3
=
1728
⇒
8
x
3
+
y
3
27
+
2
×
30
×
12
=
1728
From
1
and
2
⇒
8
x
3
+
y
3
27
+
720
=
1728
⇒
8
x
3
+
y
3
27
=
1728
-
720
⇒
8
x
3
+
y
3
27
=
1008
Hence
,
the
correct
option
is
a
.
Suggest Corrections
26
Similar questions
Q.
IF 2x+y=3 , xy=1 , then the value of
8
x
3
+
y
3
is
Q.
If
2
x
+
3
y
=
12
and
x
y
=
6
, find the value of
8
x
3
+
27
y
3
.
Q.
Factorise:
8
x
3
−
(
2
x
−
y
)
3
Q.
Factorise:
(
2
x
+
y
−
z
)
3
−
8
x
3
−
y
3
+
z
3
Q.
Find
8
x
3
+
27
y
3
, if
2
x
+
3
y
=
13
and
x
y
=
6
.
View More
Join BYJU'S Learning Program
Grade/Exam
1st Grade
2nd Grade
3rd Grade
4th Grade
5th Grade
6th grade
7th grade
8th Grade
9th Grade
10th Grade
11th Grade
12th Grade
Submit
Related Videos
Algebraic Identities
MATHEMATICS
Watch in App
Explore more
Algebraic Identities
Standard VIII Mathematics
Join BYJU'S Learning Program
Grade/Exam
1st Grade
2nd Grade
3rd Grade
4th Grade
5th Grade
6th grade
7th grade
8th Grade
9th Grade
10th Grade
11th Grade
12th Grade
Submit
AI Tutor
Textbooks
Question Papers
Install app