6y^2-7y-3-2y^2+9y+7 (pretend that you're multiplying -1 to 2y^2-9y-7 which is why 9y and 7 are positive now).
Now you're able to simplify your problem, so...
6y^2-2y^2= 4y^2
-7y+9y= 2y
-3+7=4
4y^2+2y+4 
Might want to check my math but that's how you do it.
        
             
        
        
        
Ok so if 1200 total pens and 60 were taken that's a ratio of 1200/60=20
out of 60pens 4 didn't work, again ratio is 4/60=1/15 so about 1/15 of the pens didn't work. 
so we have 1200pens * 1/15broken ratio = 80 pens or we can say 
20*4=80pens won't work from 20 groups of 60 and 4 out of 60 not working is 20*4=80 not working from total batch of 1200.
hope this helps you some! thank you!!!!!!!!!
        
             
        
        
        
Answer:
the question isnt clear
Step-by-step explanation: