Question

the difference of two numbers is 21 and their product is 4

Answer 1

Answer:

please explain your question better...

Answer 2

Answer:

ANSWER

Let the number be x and y.

x−y=4,xy=21

x

3

−y

3

=(x−y)[x

2

+y

2

+xy−2xy+2xy]

=(x−y)[(x−y)

2

+3xy]

=4(16+63)=4×79=316

x−y=4⇒ squaring on both sides x

2

−y

2

−2xy=16

⇒(x+y)

2

−2xy−2xy=16

Step-by-step explanation:

ANSWER

Let the number be x and y.

x−y=4,xy=21

x

3

−y

3

=(x−y)[x

2

+y

2

+xy−2xy+2xy]

=(x−y)[(x−y)

2

+3xy]

=4(16+63)=4×79=316

x−y=4⇒ squaring on both sides x

2

−y

2

−2xy=16

⇒(x+y)

2

−2xy−2xy=16

⇒(x+y)

2

=16+4×21

x+y=10

∴x

3

+y

3

=(x+y)[x

2

+y

2

−xy]

=(x+y)(x

2

+y

2

−xy+2xy−2xy)

(10)[(x+y)

2

−3xy]⇒10(100−63)=370

Required ratio =

x

3

−y

3

x

3

+y

3

=370:316=185:158

Hence, option 'C' is correct.