## Section 2.4 Clicker Problems

1. Which of these is a relation?

A. $\{(0,0), (0,2), (0,4), (0,6), (0,8)\}$
B. $\{(1,3), (2,6), (3,9), (4,12)\}$
C. $\{(1,0), (2,0), (3,0), (4,0), (5,0), (6,0), \dots\}$
D. All of the above

2. Which of these is a NOT function?

A. $\{(0,6), (1,5), (3,8), (4,2), (9,6)\}$
B. $\{(1,2), (3,7), (5, 7), (1,2), (-8,12)\}$
C. $\{(4,-6), (9,12), (3,1), (4,6) \}$
D. All of the above

3. Correctly complete the sentence: A function is relation...

A. if its graph passes the horizontal line test.
B. if its graph passes the vertical line test.
C. ...uh, always.
D. ...uh, never.

4. Let $f(x)=x^3-x$, where $x$ is a whole number. Evaluate $f(-2)$.

A. $f(-2) = -6$
B. $f(-2)=-4$
C. $f(-2)=10$
D. $f(-2)$ is not defined.

5. What is the domain of $\displaystyle F(x) = \frac{x-5}{\sqrt{2x-4}}$?

A. $x \ne 5$
B. $x \ne 2$
C. $x>2$
D. $x \ge 2$