Answer:
Step-by-step explanation: 5.4 feet is the fixed part of the expression
increases by 5.6feet per year is the variable part of the expression
5.4+3.6y
5.4+3.6*y
y represents the number of years= 0, 1, 2, 3..............etc
5.4 as the fixed part is always on its own in an expression without a variable.
only the variable component has a variable next to it and in this case it is y