Answer:
(a) [8, 14]
(b)  
(c)See attachment
Step-by-step explanation:
We want to choose a value of x within 3 units of 11.
(a)Now, 11-3=8 and 11+3=14
The possible values of x ranges is in the closed interval [8,14]
(b) Since x is within 3 units of 11., we have:

Solving the absolute inequality

(c)To draw the number line, we use a closed dot since we have the less than or equal to sign.
 
        
                    
             
        
        
        
Answer:0.75 milligrams will  be present in 24 hours
Step-by-step explanation:
Step 1
 The formula for radioactive decay can be written as 
N(t)=No (1/2)^(t/t 1/2)
 where 
No= The amount of the radioactive substance at time=0=milligrams
 t 1/2= the half-life= 6 hours
t=24 hours
 N(t) = the amount at time t
Step 2--- Solving
N(t)=No (1/2)^(t/t 1/2)
=N(t)=12 x ( 1/2) ^ (24/6)
= 12 x (1/2) ^4
= 12 x 0.0625
= 0.75 milligrams 
 
        
             
        
        
        
Answer will be D. Absolute value can never be negative.
        
             
        
        
        
4,646,536 is the right answer
 
        
                    
             
        
        
        
Number one is really easy just set it up in proportions. 420 over x and 7 hours over 24 cause you know there 24 hours in a day and then cross division and simplify. I think.