Respuesta :
By solving a quadratic equation, we will see that the width of the walkway must be 2 ft.
How to get the width of the walkway?
Remember that the area of a rectangle of length L and width W is:
A = L*W
In this case, we know that the dimensions are:
- Length = 8ft
- Width = 12ft
Now, if we add a walkway of width x all around the garden, the new dimensions of the garden are:
- Length = 8ft + 2x
- Width = 12ft + 2x
Now with these dimensions, the area is 192 ft^2, then we can write:
192 ft^2 = (8ft + 2x)*(12ft + 2x)
Now we need to solve that for x:
192 ft^2 = 96ft^2 + 4x^2 + 40ft*x
0 = 96ft^2 - 192ft^2 + 4x^2 + 40ft*x
0 = 4x^2 + 40ft*x - 96ft^2
This is a quadratic equation, the solutions are given by Bhaskara's formula:
[tex]x = \frac{-(40ft) \pm \sqrt{(40ft)^2 - 4*4*(-96ft^2)} }{2*4} \\\\x = \frac{-(40ft) \pm 56ft }{8}[/tex]
Notice that we have two solutions, but we only care for the positive one, so we take:
x = (-40ft + 56ft)/8 = 2ft
So the width of the walkway must be 2ft.
If you want to learn more about quadratic equations, you can read:
https://brainly.com/question/1214333