66 + 149 = 215
215/2 = 107.5
107.5 is the average.
This question is solved applying the formula of the area of the rectangle, and finding it's width. To do this, we solve a quadratic equation, and we get that the cardboard has a width of 1.5 feet.
Area of a rectangle:
The area of rectangle of length l and width w is given by:

w(2w + 3) = 9
From this, we get that:

Solving a quadratic equation:
Given a second order polynomial expressed by the following equation:
.
This polynomial has roots
such that
, given by the following formulas:
In this question:


Thus a quadratic equation with 
Then


Width is a positive measure, thus, the width of the cardboard is of 1.5 feet.
Another similar problem can be found at brainly.com/question/16995958
20x1/4=5
Think thats what you mean
F(x) = x4(x2 - 1)
f(-x) = (-x)4((-x)2 - 1)
f(-x) = x4(x2 - 1)
from above explanation it is clear that the function is even.