Question

Translate to a quadratic​ equation, then solve using the quadratic formula. The length of a rectangular air filter is 3 inches less than twice the width. Find the length and width of the filter if the area is 527 square inches.

Answer 1

Answer:

Width of the rectangle = 17 inches

Length of the rectangle = 31 inches

Step-by-step explanation:

Let w be the width of the rectangle.

Given:

Width of the rectangle = w

Length of the rectangle = 2w - 3

Area of the rectangle $=527\ inches^{2}$

Solution:

We know that the area of the rectangle.

$Area\ of\ rectangle = length\times width$

$w(2w-3)=527$

$2w^{2}-3w-527=0$

Now, we first find the root of the above equation.

Use quadratic formula with $a=2, b=-3, c=-527$.

$t=\frac{-b\pm \sqrt{(b)^{2}-4ac}}{2a}$

Put a, b and c value in above equation.

$w=\frac{-(-3)\pm \sqrt{(-3)^{2}-4(2)(-527)}}{2(2)}$

$w=\frac{3\pm \sqrt{9+8\times 527}}{4}$

$w=\frac{3\pm \sqrt{9+4216}}{4}$

$w=\frac{3\pm \sqrt{4225}}{4}$

$w=\frac{3\pm 65}{4}$

For positive sign

$w=\frac{68}{4}$

w = 17 inches

So, width of the rectangle is 17 inches.

Length of the rectangle.

$Length = 2\times w-3$

$Length = 2\times 17-3$

$Length = 34-3$

Length = 31 inches

So, length of the rectangle is 31 inches.

Therefore, width and length of the rectangle is 17 inches and 31 inches.