I assume you mean -5 and 3/4 instead of -53/4. In that case, it cannot be A, as -5.8 is less than -5.75 (AKA -5 3/4). It cannot be C or D either, though, as the number has to be less than -5.5, and -5.4 or -5.3 are both more than -5.5. Thus, by process of elimination, it has to be B, - 5.7. Hope I helped! Good luck in future!
        
             
        
        
        
For lines to be perpendicular they would need to have opposite slopes, so for a slope of -3/7 the slope of a perpendicular line would be 7/3
        
             
        
        
        
Answer:
490 students have back packs 
Step-by-step explanation:
700 / 10 = 70
70* 7 = 490