Question

(3x - 7y)³ + (3x + 7y)³ ​

Answer 1

Step-by-step explanation:

] (3x+7y)

3

+(3x−7y)

3

as (a+b)

3

=a

3

+b

3

+3ab(a+b)

(a−b)

3

=a

3

+b

3

−3ab(a−b)

=(3x)

3

+(7y)

3

+3×3x×7y(3x+7y)+(3x)

3

+(7y)

3

−3×3x×7y(3x−7y)

= 27x

3

+343y

3

+63xy(3x+7y)+27x

3

+343y

3

−63xy(3x−7y)

= 54x

3

+686y

3

+189x

2

y+441xy

2

−189x

2

y+441xy

2

= 54x

3

+686y

3

+882xy

2

Answer 2

(3x - 7y)³ + (3x + 7y)³

= 27x³ - 189x²y + 441xy² - 343y³ + 27x³ + 189x²y + 441xy² + 343y³.

= 54x³ + 882xy².

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