Final answer:
The most appropriate vertical scale for the equation y = 600 - 30x, representing the amount of money Jenna owes after x months, would range from $0 to $600 to include all values of y as x increases.
Step-by-step explanation:
The equation y = 600 - 30x indicates the amount of money (y) Jenna owes on a loan after x months. When graphing this equation, the vertical scale should reflect the range of values that y can take. Since the initial loan amount is $600, and y reduces by $30 every month, a vertical scale ranging from $0 to $600 would be most appropriate. This will cover all potential values of y as x increases. As this is a linear equation of the form y = mx + b, if plotted, the y-intercept would be 600 (the starting value of the loan), and the slope would be -30 (the amount by which the loan decreases each month).