The answer is -1975. Hope I was able to help
 
        
        
        
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
 such that  , given by the following formulas:
, 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:

Step-by-step explanation:
The additive number of any number is the number when added to the number gives a result of zero.
So, if we add 10 to -10 we get a result of zero.
=> -10+10
=> Zero
 
        
             
        
        
        
Cone volume formula: V = πr²h/3
r = radius
h = height
The radius is half the diameter, so, we can divide.
2 / 2 = 1
Now, solve with the given values.
V = π(1)²(1)/3
V = π(1)(1/3)
V = 3.14(1/3)
V ≈ 1.05
Therefore, the volume is roughly 1.05m^3
Best of Luck!
 
        
             
        
        
        
Given: ∠JNL and ∠MNK are vertical angles and  m∠MNK=90°
Prove: ∠JNL is a right angle.
    Statements                                                     Reasons
1.  ∠JNL and ∠MNK are vertical angles.             Given 
2.  Vertical angle theorem
        Vertical angle theorem
3.  Angle congruence postulate
        Angle congruence postulate
4.   Given
                Given
5.  <u> Substitution Property of Equality</u>
                 <u> Substitution Property of Equality</u>
Since, the measures of angle JNL and MNK are equal and the measure of angle MNK is 90 degrees. therefore, by substitution property of equality, both the angles JNL and MNK will have an equal measure.
Therefore,  
6. ∠JNL is a right angle.                                     Definition of right angle