Chapter 1 - Section 1.1 - Algebraic Expressions, Real Numbers, and Interval Notation - Exercise Set - Page 12: 14

$\frac{6}{10-x}$

The quotient of 6 and the difference of 10 and a number means we are dividing 6 by the difference of 10 and a number. The difference of 10 and a number can be represented algebraically as 10-x so the entire statement can be represented algebraically as $\frac{6}{10-x}$