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Candy draws a square design with a side length of x inches for the window at the pet shop. She takes the design to the printer and asks for a sign that has an area of 16x2 – 40x + 25 square inches. What is the side length, in inches, of the pet shop sign?

Verified Answer :

Answer:

The length of the sign is \((4x-5)\) inches

Step-by-step explanation:

We are given that,

Area of the square design = \(16x^2-40x+25\)

We will first find the roots of the equation \(16x^2-40x+2=0\)

The roots of the quadratic equation \(ax^2+bx+c=0\) are given by \(x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}\)

On comparing, a= 16, b= -40 and c= 25

So, the roots of the equation are,

\(x=\frac{40\pm\sqrt{(-40)^2-4\times 16\times 25}}{2\times 16}\)

i.e. \(x=\frac{40\pm\sqrt{1600-1600}}{32}\)

i.e. \(x=\frac{40\pm\sqrt{0}}{32}\)

i.e. \(x=\frac{40}{32}\)

i.e. \(x=\frac{5}{4}\)

That is, the factors of the polynomial \(16x^2-40x+25\) are \((4x-5)\) and \(4x-5\).

So, Area of the square design = \(16x^2-40x+25\) = \((4x-5)^2\)

Since, Area of a square = \(Length^2\)

Thus, the length of the sign is \((4x-5)\) inches

Answer:

B

Step-by-step explanation: