Answer: 46
Step-by-step explanation:
You can simplify this using PEMDAS:
Parentheses
Exponents
Multiplication/division
Addition/subtraction
Move through the steps in that order. 
In this case, the first two steps are absent, so multiply first:
20 - 16 + 42
Then, add and subtract:
46. 
 
        
             
        
        
        
Answer:
f(7)=10-14=-4
Answer=-4 
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
The standard deviation of weight for this species of cockroaches is 4.62.
Step-by-step explanation:
Given : A different species of cockroach has weights that are approximately Normally distributed with a mean of 50 grams. After measuring the weights of many of these cockroaches, a lab assistant reports that 14% of the cockroaches weigh more than 55 grams.
To find : What is the approximate standard deviation of weight for this species of cockroaches?
Solution : 
We have given, 
Mean 
The sample mean x=55
A lab assistant reports that 14% of the cockroaches weigh more than 55 grams.
i.e. P(X>55)=14%=0.14
The total probability needs to sum up to 1,



The z-score value of 0.86 using z-score table is z=1.08.
Applying z-score formula,

Where,  is standard deviation
 is standard deviation
Substitute the values,





The standard deviation of weight for this species of cockroaches is 4.62.
 
        
             
        
        
        
we are given 
point-A= -7
point-B=8
(a)
opposite of point-A is negative of point-A value 
so, 
opposite of point-A is -(-7)
opposite of point-A is 7
opposite of point-B is negative of point-B value 
so, 
opposite of point-B is -8
opposite of point-B is -8
(b)
we can see that 
opposite of point-A is 7
opposite of point-B is -8
they are not equal 
so, this argument is FALSE.......Answer
 
        
             
        
        
        
I think its 20 pounds per 17 square feet (simplest form)