Since the x-values increase as you move to the right on the coordinate plane, the line is defined for all real numbers greater than or equal to 0. Therefore, the domain is x .
Understand the slope and starting/ending points: The line has a negative slope, indicating it slopes downward from left to right. It starts at (0, 9) on the y-axis and exits at (8, 1).
Understand the direction on the coordinate plane: Since the line starts on the y-axis at (0, 9) and exits at (8, 1), it is moving to the right on the x-axis. Determine the domain: The line is defined for all real values of x greater than or equal to 0 because it starts at x = 0 on the y-axis and continues to the right. Therefore, the domain of the function is x .
So, the correct answer is (a) x | x ≥ 0.