question_answer

Prove that if x number is doubled then its cube is 8 times cube of the given number.

Answer:

Let y be the double of x

i.e.                     y = 2x

By using on both sides

\[{{y}^{3}}={{(2x)}^{3}}\]

\[\Rightarrow \]\[{{y}^{3}}={{2}^{3}}\times {{x}^{3}}=2\times 2\times 2\times {{x}^{3~}}\]

\[\Rightarrow \]  \[{{y}^{3}}=8{{x}^{3}}\]