Answer:
-y^4+4y
Step-by-step explanation:
 
        
             
        
        
        
That is permuations
that would be 10! or 10*9*8*7*6*5*4*3*2*1=3628800 ways
        
                    
             
        
        
        
Pie equals 3.14 so if you turn that into a fraction you will get your answer
        
                    
             
        
        
        
Step-by-step explanation:
Did you mean:
= (a - b)(a + b) 
= a.a + b.a - b.a - b.b
= a² + ba - ba - b²
= a² - b²