Respuesta :
Let w be the width of the deck. Then, using the total area, we get:
(9+2w)(18+2w)=400
4w²+54w-238=0
2w²+27w-119=0
(2w-7)(w+17)=0
w=-17 or 7/2
Using the positive value, we get a width of 3&1/2 ft. for the deck
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(9+2w)(18+2w)=400
4w²+54w-238=0
2w²+27w-119=0
(2w-7)(w+17)=0
w=-17 or 7/2
Using the positive value, we get a width of 3&1/2 ft. for the deck
☺☺☺☺
The width of the deck is [tex]3.5[/tex]feet.
Area of rectangle [tex]= length\times width[/tex]
Let [tex]x[/tex] be the width of the deck,
[tex]total\; length= 9+2x[/tex]
[tex]Total \; width = 18+2x[/tex]
Total area[tex]=400[/tex] (given)
[tex]400 = (9+2x)(18+2x)[/tex]
[tex]400=162+18x+36x+4x^2\\[/tex]
[tex]2x^2+27x+119=0[/tex]
Solve quadratic equation, we get
[tex](x-17)(x-3.5)=0[/tex]
[tex]x=-17 \; or\; 3.5[/tex]
So the width of the deck can not be negative.
Hence width of the deck is [tex]3.5[/tex] feet.
Learn more about rectangle here;
https://brainly.com/question/15019502?referrer=searchResults