Given:
The length of your family's garden is 3 feet greater than the width.
The area of the garden is 460 square feet.
To find:
The dimensions of the garden.
Solution:
Let x feet be the width of the garden. Then,
Length = [tex]x+3[/tex] feet
The area of a rectangle is:
[tex]A=l\times w[/tex]
Where, l is the length and w is the width of the rectangle.
The area of the rectangular garden is:
[tex]A=(x+3)\times x[/tex]
[tex]A=x^2+3x[/tex]
It is given that the area of the garden is 460 square feet.
Putting [tex]A=460[/tex], we get
[tex]460=x^2+3x[/tex]
[tex]0=x^2+3x-460[/tex]
Splitting the middle term, we get
[tex]x^2+23x-20x-460=0[/tex]
[tex]x(x+23)-20(x+23)=0[/tex]
[tex](x+23)(x-20)=0[/tex]
[tex]x=-23,20[/tex]
The width of a garden cannot be negative. So, [tex]x=20[/tex].
Now,
[tex]l=x+3[/tex]
[tex]l=20+3[/tex]
[tex]l=23[/tex]
Therefore, the length of the garden is 23 feet and the width of the garden is 20 feet.