John planted a 4 foot tree in his backyard. The tree grows at a constant rate of 2 feet every 5 weeks.

There is not an actual question here, so i will answer this in a general way.

The initial height of the tree is 4 ft.

We know that every 5 weeks, the tree grows 2 ft

Then the rate at which the tree grows can be calculated as:

R = (how much it grows)/(in how much time)

Then:

R = (2 ft)/(5 weeks) = 0.4 ft/week

This means that the tree grows 0.4 feet per week.

Then we can write the equation:

H(w) = 4ft + (0.4ft/week)*w

Where w is the number of weeks since John planted the tree.

So if we want to know the height of the tree in a particular week, like week 3, we just need to replace w by 3 weeks in the above equation:

H(3 weeks) = 4ft + (0.4 ft/week)*(3 weeks)

                   = 4ft + 1.2 ft = 5.2 ft