Answer: 6x+5y=28
Step-by-step explanation:
Looking at the first equation, we can tell that x stands for notebooks and y stand for pens. Since this talks about the total cost with the amount of products they bought, we can automatically eliminate the subtracting answer choices. 
Now, we know that 6x+57=28 is the correct answer because Sonja bought 6 notebooks and 5 pens. This becomes 6x+5y.
 
        
             
        
        
        
Answer: -3, -2.5, -1, 2, 5.
Explanation: 
The number line goes from the smallest number to the largest number. As an example you may ask why -3 is smaller than -1 even though it looks larger. This is because it actually isn’t since it is negative. When a number is negative, the higher the number are the smaller it is. One more example could be that -10 is smaller than -5.
        
                    
             
        
        
        
Answer:
The value of the exterior angle is 
Step-by-step explanation:
we know that
The sum of the interior angle plus the exterior angle is equal to  , because are supplementary angles.
, because are supplementary angles.
Let
x-----> the measure of the exterior angle
so

solve for x

 
        
             
        
        
        
<u>Answers:</u>
These are the three major and pure mathematical problems that are unsolved when it comes to large numbers.
The Kissing Number Problem: It is a sphere packing problem that includes spheres. Group spheres are packed in space or region has kissing numbers. The kissing numbers are the number of spheres touched by a sphere.  
The Unknotting Problem: It the algorithmic recognition of the unknot that can be achieved from a knot. It defined the algorithm that can be used between the unknot and knot representation of a closely looped rope.
The Large Cardinal Project: it says that infinite sets come in different sizes and they are represented with Hebrew letter aleph. Also, these sets are named based on their sizes. Naming starts from small-0 and further, prefixed aleph before them. eg: aleph-zero.
 
        
             
        
        
        
Answer:
The point will move to the left 4 place values.
Step-by-step explanation:
When you add or subtract from the x value, you are moving the point parallel to the x-axis, the amount you need to go. If subtracting, you move left, if adding, you move right. 
When you add or subtract from the y value, you are moving the point parallel to the y-axis, the amount you need to go. If subtracting, you move down, if adding, you move up. 
~