The product rule of Integer Exponents states that when multiplying two numbers with the same base raised to different exponents, we can add the exponents. In other words, for any positive integer a and any integers m and n, we have:
a^m * a^n = a^(m+n)
Using the product rule, we can find the numerical equivalent of 12^-5 * 12^7 as follows:
12^-5 * 12^7 = 12^(-5 + 7)
= 12^2
= 144
In this case, we used the product rule to add the exponents of 12. The exponent of the first 12 is -5, and the exponent of the second 12 is 7. By adding these exponents together, we get 2. Therefore, 12^-5 * 12^7 is equal to 144.