Given:
Width of a garden = 10 feet
Length of the garden = 14 feet
Area of the garden and the walkway together = 396 square feet.
To find:
The width of the walkway.
Solution:
A cement walkway is added around the outside of the garden.
Let x be the width of the walkway.
The width of the garden with walkway = 10+2x
The length of the garden with walkway = 14+2x
Area of a rectangle is

Area of garden and the walkway together is




Divide both sides by 4.



Splitting the middle term, we get



Using zero product property, we get


Width of walkway cannot be negative. So, x=4.
Therefore, the width of the walkways is 4 feet.