1 Answer

Zappa · Answer 1 · 2023-12-18T03:43:24+0000

The area of the border is equal to

Expand the equation

$\begin{gathered} A=640+64x+40x+4x^2-640 \\ A=4x^2+104x \end{gathered}$

Remember that the area of the border is given

A=224 ft2

substitute and solve the quadratic equation

$\begin{gathered} 4x^2+104x=224 \\ 4x^2+104x-224=0 \end{gathered}$

using the formula

a=4

b=104

c=-224

substitute

$x=(-104\pm√(104^2-4(4)(-224)))/(2(4))$
$x=(-104\pm120)/(8)$

The values of x are

x=2 ft and x=-28 ft ( is not a solution because is a negative number)

therefore

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