A farmer has a rectangular garden plot surrounded by 200 ft of fence. Find the length and width of the garden if its area is 2475 ft2.

Respuesta :

Answer:

[tex]l =45[/tex] --- length

[tex]w = 55[/tex] --- width

Step-by-step explanation:

Given

[tex]P = 200[/tex] --- perimeter

[tex]A = 2475[/tex] --- area

Required

The dimension of the farm

Let

[tex]l \to length; w \to width[/tex]

So:

[tex]p = 2(l+w)[/tex] --- perimeter

[tex]2(l+w)=200[/tex]

Divide by 2

[tex]l+w=100[/tex]

Make l the subject

[tex]l = 100 - w[/tex]

Also:

[tex]A= l*w[/tex] --- area

[tex]l * w = 2475[/tex]

Substitute: [tex]l = 100 - w[/tex]

[tex](100 - w) * w = 2475[/tex]

Open bracket

[tex]100w - w^2 = 2475[/tex]

Rewrite as:

[tex]w^2 - 100w +2475 = 0[/tex]

[tex]w^2 - 45w - 55w +2475 = 0[/tex]

Factorize

[tex]w(w - 45) - 55(w -45) = 0[/tex]

Factor out w - 45

[tex](w - 55)(w -45) = 0[/tex]

Take any one of the expression and solve for w

[tex]w -55 = 0[/tex]

[tex]w = 55[/tex]

Recall that: [tex]l = 100 - w[/tex]

[tex]l =100 - 55[/tex]

[tex]l =45[/tex]

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