He made a mistake in step #2. It seemed to be a trivial mistake because it involved signs, but it still had a great impact. Since step#2, his solution was already wrong.
Instead of
(-1)²-4(2)(-6) = 1 + 48 = 49
What he did is
(-1)²-4(2)(-6) = -1 + 48 = 47
        
             
        
        
        
Answer:
A. Sheila lives closer to the library
Step-by-step explanation:
 
        
             
        
        
        
72/6+ 85/6
= (72+ 85)/6
= 157/6
= (156+1)/ 6
= 156/6+ 1/6
= 26+ 1/6
= 26 1/6
The final answer is 26 1/6~
        
                    
             
        
        
        
Long Piece: x + 18
Short Piece: x
(x) + (x + 18) = 84
2x + 18 = 84
2x = 66
x = 33
Long Piece: x + 18  = (33) + 18   = 51
Answer: 33 meters and 51 meters