Answer:
The difference of squares is (a - b)(a + b) = a² - b². Since a = x and b = 2, the answer is x² - 4.
 
        
                    
             
        
        
        
There are 52 cards in a deck, half the cards aware red and half the cards are red.
First card being red is 26/52 = 1/2
After the first card is dealt there are 51 cards left and 26 are black so dealing a black card = 26/51
After 2 cards are dealt there are 50 cards left and 25 red ones left. The probability would be 25/50 = 1/2
The probability of all 3 happening = 1/2 x 26/51 x 1/2 = 13/102
Answer: 13/102
 
        
             
        
        
        
8+5+8=21 coins in total.
8/21*7/20=
56/420=
2/15. Hope this helps, and PM me if something's not clear!