Answer:
The length, in feet, of the side of the garden that is against the wall is(60 - x - CD) ft.
Explanation:
Consider the diagram below.
The wall is labelled as AD, the side perpendicular to the wall is labelled as AB and the side against the wall is labelled as CB.
It is provided that the rectangular garden is enclosed by 60 feet of fencing on three sides.
That is,
AB + CB + CD = 60 ft.
⇒ x + CB + CD = 60 ft.
Then the length, in feet, of the side of the garden that is against the wall is:
x + CB + CD = 60 ft.
⇒ CB = (60 - x - CD) ft.