The blank: 

You can combine the negative 78 and 9 if you want to, but that should be the next step for that problem.
 
        
        
        
Hello!
-7 + 4 = -3
I hope this helps you! Have a lovely day!
-Mal
 
        
                    
             
        
        
        
Answer:
 First option: 
Step-by-step explanation:
<h3>
 The complete exercise is: "The height of a hill, h(x), in a painting can be written as a function of x, the distance from the left side of the painting. Both h(x) and x are measured in inches 
. What is the height of the hill in the painting 3 inches from the left side of the picture?</h3>
 
 You have the following function provided in the exercise:
 
 You know that  represents the height of the hill (in inches) and "x" represents the distance from the left side of the painting (in inches)
 represents the height of the hill (in inches) and "x" represents the distance from the left side of the painting (in inches)
 Knowing that you can determine that, if the painting 3 inches from the left side of the picture, the value of "x" is the following:
 
 Therefore, you need to find the value of    when
 when   in order to solve this exercise.
 in order to solve this exercise.  
 So, the next step is to substitute   into the function:
 into the function:
 
 And finally, you must evaluate in order to find  .
. 
 You get that this is:
 
 
        
                    
             
        
        
        
2L+2W=157.5
L=W-30
2(W-30)+2W=157.5
2W-60+2W=157.5
      +60           +60
4w=217.5
 W=54.4(.37 rounded to nearest tenth)
  L=24.4
        
             
        
        
        
12.9 = x + 7.1
subtract 7.1 from both sides to isolate the variable, x.
5.8 = x
5.8 is your answer.