We can use algebra.
So, what rate time 1.20 = .80
Let x = the rate (in a decimal form)
1.20x = .80
x = .6666666666
Now, we need to multiply by 100 to get a percentage.
66.66 The price is 66% of the regular price.
They marked it off 
33.33%
 
        
                    
             
        
        
        

Substitute the values of x to the equation of the function f:

Therefore we have two points (-1, 7) and (2, 1).
We can calculate the slope of line l.
The formula of a slope:

Substitute:

<h3>Answer: A) -2.</h3>
 
        
             
        
        
        
Answer:
Step-by-step explanation:
The area of a regular polygon is 
 where a is the apothem and p is the perimeter. Perimeter is simple: just count the number of sides the polygon has and multiply it by 3 (the length of one side).
 where a is the apothem and p is the perimeter. Perimeter is simple: just count the number of sides the polygon has and multiply it by 3 (the length of one side).
p = 3(9) is 27 inches for the perimeter.
We have what we need now to find the area:
 and
 and
 so
 so 
A = 55.35 square inches
 
        
             
        
        
        
the difference between a full jug and a jug that is half full will give us the weight of the marbles only in a half full jug: 
4 - 2.6 = 1.4 kg 
 In a half full jug that weighs 2.6 kg, the weight of the marbles is 1.4 kg 
 the weight of the jug = 2.6 - 1.4 = 1.2 kg
 
        
                    
             
        
        
        
The answer is 4.
The easiest way to determine the value of statements like this is to turn the percentage into a decimal and then multiply. 
20% * 20
.20 * 20
4