During a sleepover, Baylie played karaoke with her friends. Her song was 4 minutes long. She had already sung for 3 minutes. Which equation could be used to see how much longer she will have to sing?

The equation that could be used to see how much longer Baylie will have to sing is:

Remaining Time = Total Time - Time Already Served

In this case, Baylie's Remaining Time can be represented as 'x', the Total Time as '4 minutes', and the Time Already Served as '3 minutes'. Therefore, the equation becomes:

x = 4 - 3

Simplifying, we get:

x = 1

So, Baylie will have to sing for 1 more minute.