Jason builds doghouses for a pet store. Each doghouse is a wooden structure with a rectangular base that has an area of 21 square feet and a length that is 4 feet more than its width.

If x represents the width of the doghouse, write an equation in the given form that can be used to determine the possible dimensions of the base of the doghouse.

(Platform is Plato)

x (x+4) = 21, or x²+4x-21 = 0

Step-by-step explanation:

The area of a rectangle is given by multiplying the length and width of the rectangle. We know that the length is 4 more than the width; if x represents the width, this means that the length is x+4.

The area would then be x (x+4). We know that the area equals 21; this gives us the equation

x (x+4) = 21

Using the distributive property, we have

x (x) + x (4) = 21

x²+4x = 21

To write in standard form, subtract 21 from each side:

x²+4x-21 = 21-21

x²+4x-21 = 0

Answer: x * (x+4) = 21

Step-by-step explanation:

x = width

x+4 = length

area=length * width