Multiply 4 * 5, which equals 20, and add the two zeroes(from 40 and 50) on the end.
That gives us:
2000
        
                    
             
        
        
        
11111111111111117373646328299292922
        
             
        
        
        
The x is going to be a negative number to get the 3. so start off minus 5 from plus 5 and minus five from the other side too. the positive 5 and the negative cancel out and then take it fromt here with three and the negative 5. 
        
                    
             
        
        
        
Answer:
As a fraction, the answer is exactly 86/969
In decimal form, the answer is approximately 0.08875
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Work Shown:
The assumption is that no replacements are made for each selection.
5 red, 6 blue, 8 green
5+6+8 = 19 total
A = P(3 red) = (5/19)*(4/18)*(3/17) = 10/969
B = P(3 blue) = (6/19)*(5/18)*(4/17) = 20/969
C = P(3 green) = (8/19)*(7/18)*(6/17) = 56/969
D = P(3 all same color) 
D = A+B+C
D = 10/969 + 20/969 + 56/969
D = (10+20+56)/969
D = 86/969
D = 0.08875