This is what I think:
#1: 800 - 50 = 750
#2: 800 divided by 2 = 400 - 50 = $350
 
        
                    
             
        
        
        
        
The first digit of a number can be 1-9. The 2nd and the 3rd digit can be 1-10. The last digit can be 0 or 5 ( 2 numbers ):
9 * 10 * 10 * 2 = 1,800
She could pick 1,800 different 4-digit numbers.
        
             
        
        
        
Answer:
6 -7
-7
Step-by-step explanation:
simplyifying this we get
1+5i-8+i
= 6i-7
I am assuming the i you are talking about here is the sqrt of negative one so that would be 6 -7
-7
 
        
             
        
        
        
The half-life of the radioactive substance is 67.95 hours.