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
So the solid consist of 1 pentagon, 5 congruent equilateral triangle and 5 congruent squares and has 11 vertices so the number of edges of this solid is 20. I hope you are satisfied with my answer and feel free to ask form more if you have more clarifications.
Answer:

Step-by-step explanation:
The most straightforward way is direct substitution of g(x) for x in f(x):

Answer:
28. 120 degrees
29. 30 degrees
30. 56 degrees & 124 degrees
31. 72 degrees, 108 degrees, and 18 degrees
Step-by-step explanation:
We assign variable x for the answer we are looking for (28-29).
28.
Supplement means x + y = 180 degrees. We also know x = 2y. Substitution gives us 3y = 180 degrees, so y = 60 degrees and x = 120 degrees.
29.
Complement means x + y = 90 degrees. We are given 2x = y. Substitution brings us 3x = 90 degrees, x = 30 degrees.
30.
Supplement means x + y = 180 degrees. We are told that y = 2x + 12, so we substitute. This gives 3x + 12 = 180 degrees, x = 56 degrees. Substituting that back into the equation for y, we get 124 degrees.
31.
Supplement means x + y = 180 degrees. Complement means x + z = 90 degrees. Using our given info, we know y = 6z. We can substitute that in to get x + 6z = 180. Subtracting our second and third equations, we get 5z = 90, z = 18 degrees. Therefore, x = 72 degrees, y = 108 degrees.
Answer:
The two numbers are 52 and 12.
Step-by-step explanation:
x+y=64
x=16+3y
Now, substitute the second equation into the first one.
16+3y+y=64
16+4y=64
4y=48
y=12
Substitute 12 into one of the equations in order to find x.
x=16+3(12)
x=16+36
x=52