Question

show that if a number is doubled then its cube becomes 8 times the cube of the given number​

Answer 1

Answer:

Step-by-step explanation:

let The no=x and its cube=y

then y=x³

now x is doubled to 2x

so new no=2x

cube of new no=

(2x)³ =2³*x³

=8x³

=8y

=8*cube of original no

hence cube is 8 times if no is doubled

Answer 2

Answer:

To prove: If a number is doubled then its cube is 8 times the cube of the given number.

Proof: Let the number be 'a'

The double of the number = 2a

Cube of the number = a3

According to the given problem, 

Cube of 2a (double of the number) = ( 2a)3 

                                                        = 8 a3 

                                                        = 8 x ( cube of the  number )

                                                        = 8 times the cube of the number

Hence Proved.