Maths class 9 please answer
Attachments:
Answers
Answered by
1
(3x+4y)
3
−(3x−4y)
3
−216x
2
y
We know: (a+b)
3
=a
3
+b
3
+3a
2
b+3ab
2
And (a−b)
3
=a
3
−b
3
−3a
2
b+3ab
2
So,
⇒27x
3
+64y
3
+108x
2
y+144xy
2
−(27x
3
−64y
3
−108x
2
y+144xy
2
)−216x
2
y
⇒128y
3
+216x
2
y−216x
2
y
⇒128y
3
3
−(3x−4y)
3
−216x
2
y
We know: (a+b)
3
=a
3
+b
3
+3a
2
b+3ab
2
And (a−b)
3
=a
3
−b
3
−3a
2
b+3ab
2
So,
⇒27x
3
+64y
3
+108x
2
y+144xy
2
−(27x
3
−64y
3
−108x
2
y+144xy
2
)−216x
2
y
⇒128y
3
+216x
2
y−216x
2
y
⇒128y
3
Similar questions