We must find UNIQUE combinations because choosing a,b,c,d... is the same as d,c,b,a...etc.  For this type of problem you use the "n choose k" formula...
n!/(k!(n-k)!), n=total number of choices available, k=number of choices made..
In this case:
20!/(10!(20-10)!)
20!/(10!*10!)
184756
        
                    
             
        
        
        
Answer:
 slope-intercept form: y=5x-3 point-slope form: y-7=5*(x-2)
Step-by-step explanation:
Y-y1=m(x-x1)
plug in the values and you get y=5x-3
 
        
                    
             
        
        
        
Ok so... what wait weres the pic??
        
             
        
        
        
(8z - 10) ÷ (-2) + 5(z - 1) = 8z - 10 ÷ -2 + 5z - 5 = 8z + 5 + 5z - 5 = 13z
        
             
        
        
        
Answer:
9x5=45 D is ur answer 
Step-by-step explanation:
brainliest???