Question

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

Answer 1

if 2 is double then that become 4 and a cube has 4 sides then 4×2 =8

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.