Answer: $2
Step-by-step explanation:
In a linear equation with the form: y = ax + b, a represents the rate charged per quantity of x and b is the constant and initial figure.
This means that when x is 0, b is the value of the equation.
In this scenario, even if a person has not started their kayaking activity (x is 0), they will still have to pay $2 for the lifejacket meaning that this $2 is the constant value or rather the value of b.