The exponent cannot be added to the product because it stated in the law of exponents. An exponent is simply the shorthand in multiplying your base number. Exponent will give how many times you will multiply the base numbers. It is not possible that you add both exponents in the given situation because they have different value together.
=> 12^3 x 11^3
If we solve this equation following the rule of exponent will get the correct answer:
=> (12 x 12 x 12) x (11 x 11 x 11)
=> 1728 X 1331
=> the answer is 2 299 968
But if we add the exponent, the answer would be wrong
=> 12^3 x 11^3
=> 132^6
=> 5289852801024 which is wrong.