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?

Answer:

the length of the sign is $4x-5$ inches

Step-by-step explanation:

Given

Area of the square of design = $16x^{2} -40x+25$

First we find the roots of equation $16x^{2} -40x+25=0$

The roots of the quadratic equation $ax^{2} +bx^{2} +c=0$ are given by

$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$

where $a=16, b=-40, c=25$

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

$x=\frac{40\pm\sqrt{1600-1600}}{32}$

$x=\frac{40\pm\sqrt{0}}{32}$

$x=\frac{40}{32}$

$x=\frac{5}{4}$

$4x=5\\4x-5=0$

That is, the factors of the polynomial $16x^{2} -40x+25$ are $4x-5$ and $4x-5$ .

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

Area of a square = Length^2

Thus, the length of the sign is $4x-5$ inches

7 0

3 years ago

A rectangle swimming pool is 8 feet deep. One side of the pool is 4.5 times longer than the other. The amount of water needed fo

wel

The side lengths of the pool 10 ft and 45 ft.

<u>SOLUTION: </u>

Given, a rectangle swimming pool is 8 feet deep.

One side of the pool is 4.5 times longer than the other.

Let the length of pool be n feet, the width will be 4.5n feet

The amount of water needed for the swimming pool is 3600 cubic ft

We have to find the dimensions of the pool. Now, we know that,

$\begin{array}{l}{\text {volume of pool}=\text {depth} \times \text {length } \times \text {width}} \\\\ {\rightarrow 3600 \text { cubic } f t=8 \text { feet } \times \text { n feet } \times(4.5 n) \text { feet }} \\\\ {\rightarrow 8 n \times 4.5 n=3600} \\\\ {\rightarrow 36 n^{2}=3600} \\\\ {\rightarrow n^{2}=100}\end{array}$

On taking square root on both sides we get,

$\begin{array}{l}{\rightarrow\sqrt{n^{2}}=\sqrt{100}} \\\\ {\rightarrow n=10 \mathrm{ft}}\end{array}$

So, the width will be $4.5 n=4.5 \times 10=45 \mathrm{ft}$

5 0

3 years ago