Answer:
5 years
Step-by-step explanation:
Since the tree grows 4 feet every single year and the second year it was 12 feet tall then that means that when you bought the tree it was 8 feet tall (12-4 = 8). Therefore, using these values we can write an equation to calculate the number of years it will take for the height of the tree to be 28 feet. We do this by multiplying 4ft by the variable of a number of years (x) and then adding that product to 8ft which is the initial height. All of which should add up to 28 ft.
28 ft. = 8 ft. + 4x ... subtract both sides by 8
20 ft. = 4x ... divide both sides by 4
5 years = x
Explanation: