To multiply, we need to add the exponents of the same base. In this case, the base is 16 since it is in hexadecimal. The exponent of b is 1 in the first term and 9 in the second term, so we add them to get 10. Therefore, the answer is 11ebbb8f_b97b_8749_bcf2_57abbf8e0f06_TB8306_11.