Final answer:
The linear equation modeling the taxi cost in Dallas with a flat fee and a cost per mile is y = 3 + 0.75x, where 'y' is the total cost and 'x' is the number of miles.
Step-by-step explanation:
The linear equation that models the cost of using a taxi in Dallas, Texas, with a flat fee of $3.00 and $0.75 per mile can be represented as y = 3 + 0.75x. In this equation, 'y' represents the total cost of the taxi ride, and 'x' represents the number of miles traveled.
The flat fee, which is the cost of using the taxi regardless of the distance, constitutes the y-intercept, while the slope of the equation is determined by the cost per mile, $0.75, indicating the rate at which the total cost increases for each additional mile traveled.