Solve this and explain it for me

Answer:
1 year.
Step-by-step explanation:
set up an expression for each in terms of x, where x is the number of years gone by.
for type a, it starts at 5 feet, and grows 9 inches per year.
so 5 + 9x = total height after x years
for type b, it starts at 8 feet and grows 6 inches per year, so 8 + 6x = total height after x years.
we want to find after how many years will they have the same so set them equal to each other and solve for x.
9x + 5 = 6x + 8
3x = 3
x = 1