Final answer:
The equation in slope-intercept form representing the situation is y = -150w + 4200.
Step-by-step explanation:
To write the equation in slope-intercept form, we need to determine the slope and the y-intercept. In this situation, Bruce Wayne starts with $4200 and spends $150 each day. The amount of money he has left on day w can be represented by the equation y = -150w + 4200, where y is the amount of money left and w is the number of days.