Answer:
160,170 and 240,250 
Step-by-step explanation:
sorry if wrong 
 
        
             
        
        
        
Answer:
97/4
Step-by-step explanation:
 
        
                    
             
        
        
        
Answer:
85%
Step-by-step explanation:
- Calculate how many students passed on their first try. 20 x 70% is 14, so 14 students passed on their first try.
-  6 students retook the test. Half of 6 is 3. Add 3 to the 14 students that passed earlier.
- Calculate the percent with the equation 17/20 = 0.85. 0.85 = 85%.
 
        
             
        
        
        
I think it would be y=5/6 - 5
        
             
        
        
        
-5x +2/9 +2x- 2/9 =7/9
collect like terms
-3x+0=7/9
cross-multiply
-27x=7
solve for x
x=-7/27