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A rectangular garden is 5 ft longer than twice its width. It has a sidewalk 3 feet wide on two of
the sides. The area of the sidewalk is 213 square feet. Find the dimensions of the garden.
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x - 2y = 5, (1)
(x+3)*(y+3) - xy = 213. (2)
Simplify (2) by opening the parentheses
(x+3)*(y+3) - xy = 213, or
xy + 3x + 3y + 9 - xy = 213, or
3x + 3y = 213-9, or
3x + 3y = 204, or
x + y = 68. (3)
Now you have this system of two equations in two unknowns
x - 2y = 5, (1)
x + y = 68. (3)
Distract the equation (1) from the equation (3). You will get
3y = 68 - 5 = 63.
From this point, please complete the solution on your own.