Y=3x Because it’s a linear equation so it should be that. Explanation: 3 miles every hour so at 0 hours it was 0 miles but at 1 it is 3 because it was multiples but 3. So at 2 hours they would be 6 miles off shore.
If y is the total distance from the shore and it increases by 3 miles every hour, then by plugging in the amount of hours that have passed into x we will find the distance they have traveled. For example, if they have been out for 5 hours then you would do y=3(5) which would be 15 miles from the shore.