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
Answer:
Writing expressions | Math (article) | Khan Academy
Step-by-step explanation:
Answer:
x =
, 
Step-by-step explanation:
First, isolate the absolute value:
5|2x - 7| = 20
divide both sides by 5:
|2x - 7| = 4
break into 2 equations:
2x - 7 = 4, 2x - 7 = -4
solve both equations and collect solutions:
2x = 11, 2x = 3
x =
, 
5x² + 5x + 2x + 2
5x(x + 1) + 2(x + 1)
(5x + 2)(x + 1)
Answer:
2/9
Step-by-step explanation:
16/72 simplify in calculator =2/9