To prove the identity, we need to simplify both sides of the equation and show that they are equal.

Starting with the left side of the equation:

4.8(5x - 7y) - (2/21) (4.9x + 5/18 4.5y - 23) - (8/15)x

= 24x - 33.6y - (0.933x + 1.25y - 23/21) - (8/15)x

= 24x - 33.6y - 0.933x - 1.25y + 23/21 - 8/15x

= 23.067x - 34.85y + 1.095

Now simplifying the right side of the equation:

-32.35y

Both sides of the equation are not equal. Therefore, the given equation is not an identity.