Question

find the cube of 2x + 3y​

Answer 1

e know that the identity is (a+b)  

3

=a  

3

+b  

3

+3a  

2

b+3ab  

2

 

Therefore,

(2x+3y)  

3

=(2x)  

3

+(3y)  

3

+(3×(2x)  

2

×3y)+(3×2x×(3y)  

2

)=8x  

3

+27y  

3

+(9y×4x  

2

)+(6x×9y  

2

)

=8x  

3

+27y  

3

+36x  

2

y+54xy  

2

 

Hence, (2x+y)  

3

=8x  

3

+27y  

3

+36x  

2

y+54xy  

2

.

Answer 2

Answer:

ANSWER

We know that the identity is (a+b)

3

=a

3

+b

3

+3a

2

b+3ab

2

Therefore,

(2x+3y)

3

=(2x)

3

+(3y)

3

+(3×(2x)

2

×3y)+(3×2x×(3y)

2

)=8x

3

+27y

3

+(9y×4x

2

)+(6x×9y

2

)

=8x

3

+27y

3

+36x

2

y+54xy

2

Hence, (2x+y)

3

=8x

3

+27y

3

+36x

2

y+54xy

2

.