Question

you are building a rectangular dog pen with an area of 90 ft^2. you want the length of the pen to be 3 ft longer than twice its width. which equation can you use to find the width of the pen?

Answer 1

Set up equations.
90=l*w
l = 2w+3
substitute the second equation into the area equation and solve for w

Answer 2

Equation which can be used to find the width of the pen is:

2w²+3w-90=0

Explanation:

You are building a rectangular dog pen, the length of the pen is 3 ft longer than twice its width.

Let w be the width of the pen

and l be the length

Then, l=2w+3

Also, Area of pen=90 ft²

i.e. lw=90

⇒ (2w+3)w=90

or 2w²+3w=90

or 2w²+3w-90=0

Hence, equation which can be used to find the width of the pen is:

2w²+3w-90=0