Explain how you would write a two-variable linear equation for this situation.

Answer:

To write the equation, I first identified the independent variable as the number of days (x) and the dependent variable as the number of petri dishes (y). The initial value is 185 petri dishes at 0 days, which represents the y-intercept (0, 185). Since the number of petri dishes decreases by 12 each day, the slope (m) is -12. Using the slope-intercept form, y = mx + b, the equation for this situation is y = -12x + 185.