Question 43 Answer and Explanation _ACT January 2009 Form 61F Math Section

Use the following information to answer questions 42-44.

Consider the rational function f(x) = $\frac{{x}^{2}-9}{x-7}$ , whose graph is shown in the standard (x, y)coordinate plane below.

43. What is the domain of f(x)?

(Note: The domain of a function is all the x-values for which the function is defined.)

A. All real values of x except +3

B. All real values of x except $\frac{9}{7}$

C. All real values of x except 7

D. All real values of x except +3 and 7

E. All real values of x where x ≤ -6 or x ≥ 8

Answer and Explanation

Your Answer is

Correct Answer is C

Explanation

It can be seen from the question that when x=7, the denominator of the function is 0, so x is not equal to 7, and other conditions are true. Therefore choose C