Step-by-step explanation:
In Python, the `**=` operator is used for exponentiation assignment. So, `a **= 3` is equivalent to `a = a ** 3`. Therefore, if `a = 5`, executing `a **= 3` will result in `a` being reassigned to the value of 5 raised to the power of 3, which is 125. So, the new value of `a` is 125.
