# Chapter 1 - Section 1.7 - Combinations of Functions; Composite Functions - Exercise Set - Page 258: 23

$(-\infty, 12]$

#### Work Step by Step

The radicand (expression inside a radical sign) of a square root cannot be negative as its root is an imaginary number. This means that the radicand, which is $24-2x$, must be greater than or equal to 0. Thus, $24-2x\ge 0 \\-2x \ge 0-24 \\-2x \ge -24$ Divide both sides by $-2$. Note that since a negative number is being divided on both sides of an inequality, the inequality sign flips to the opposite direction. $\dfrac{-2x}{-2} \le \dfrac{-24}{-2} \\x \le 12$ Therefore, the domain of the given function is $(-\infty, 12]$.

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