Answer: 
 Write the expression as:" 
70  +                          2
 +                          2 * 2
 * 2 − 18a
 − 18a " ; 
______________________________________________________or;  write as:
______________________________________________________           " 
70.32  + (2.1) * (2.7)  − 18a " ; 
______________________________________________________To simplify:
______________________________________________________  Using "PEDMAS" (the "order of operations") ; 
the "multiplication" comes first; 
So:  →  "(2.1) * (2.7) =  5.67 " .
And rewrite:
______________________________________________________ " 70.32  + 5.67 − 18a " .
Now:  " 70.32 + 5.67 = 75.99 " ; 
So, we can the final simplified expression as:
______________________________________________________   " 
75.99  −  18a " ;  
or; write as:  " 
75 −  18a
  −  18a " .
______________________________________________________
 
        
        
        
All you have to do is multiply 18.3 x 5.1
18.3×5.1=93.33
It will take 93.33 minutes to repair the entire section. Hope that helps!
 
        
                    
             
        
        
        
Answer:
a) 

And we want the probability from 0 to two deviations above the mean and we got 95/2 = 47.5 %
b) 

So one deviation below the mean we have: (100-68)/2 = 16%
c) 

For this case below 2 deviation from the mean we have 2.5% and above 1 deviation from the mean we got 16% and then the percentage between -2 and 1 deviation above the mean we got: (100-16-2.5)% = 81.5%
Step-by-step explanation:
For this case we have a random variable with the following parameters:

From the empirical rule we know that within one deviation from the mean we have 68% of the values, within two deviations we have 95% and within 3 deviations we have 99.7% of the data. 
We want to find the following probability:

We can find the number of deviation from the mean with the z score formula:

And replacing we got


And we want the probability from 0 to two deviations above the mean and we got 95/2 = 47.5 %
For the second case:


So one deviation below the mean we have: (100-68)/2 = 16%
For the third case:

And replacing we got:


For this case below 2 deviation from the mean we have 2.5% and above 1 deviation from the mean we got 16% and then the percentage between -2 and 1 deviation above the mean we got: (100-16-2.5)% = 81.5%
 
        
             
        
        
        
The equation of a circle is written as ( x-h)^2 + (y-k)^2 = r^2
h and k is the center point of the circle and r is the radius.
In the given equation (x+3)^2 + (y-1)^2 = 81
h = -3
k = 1
r^2 = 81
Take the square root of both sides:
r = 9
The center is (-3,1) and the radius is 9