To solve for the missing exponent in the expression \( 7^? \div 7^5 = 7^{12} \), we can use the laws of exponents.
Using the rule of exponents that states \( a^m \div a^n = a^{m-n} \), we can rewrite the left side of the equation as:
\[ 7^{? - 5} = 7^{12} \]
Since the bases are the same (both are \( 7 \)), we can set the exponents equal to each other:
\[ ? - 5 = 12 \]
Now, solve for \( ? \):
\[ ? = 12 + 5 \] \[ ? = 17 \]
Therefore, the missing number is \( 17 \).