Answer:
47
Step-by-step explanation:
There are total 52 cards. 
Certain number of cards are lost.
When divided by 4, leaves 3 cards remain ; 51, 47, 43, 39, . . .
When divided by 5, leaves 2 cards remain : 47, 42, 37, 32, . . .
When divided by 3, leaves 2 cars remain : 50, 47, 44, 41, . . .
The common number among the three is 47. 
 
        
             
        
        
        
       2b                     2a
----------------- +  -----------------
   (b+a)^2            (b^2 - a^2)
            2b                     2a
= ----------------- +  -------------------
      (b+a)(b+a)         (b+a)(b-a)
         2b(b - a) +  2a(b + a)
= ------------------------------------
           (b+a)(b+a)(b-a)
         2b^2 - 2ab  +  2ab + 2a^2
= ---------------------------------------
           (b+a)(b+a)(b-a)
         2b^2 + 2a^2
= ------------------------
        (b+a)(b+a)(b-a)
         2(b^2 + a^2)
= ------------------------
        (b+a)^2 (b-a)
Answer:
Numerator:        2(b^2 + a^2)
Denominator:    (b+a)^2 (b-a)
        
             
        
        
        
The answer is 3x-3. You have to distribute the 3 to both of the variables in the equations. The 1 in the parentheses is a negative and multiplying the 3 will result in a negative 3.
        
             
        
        
        
Answer:
cos X = 
Step-by-step explanation:
simplify 15/39
 
        
                    
             
        
        
        
Answer:
Two
Step-by-step explanation:
x² + 4 = 4x + 1
x² - 4x + 3 = 0
x² - 3x - x + 3 = 0
x(x - 3) - (x - 3) = 0
(x - 3)(x - 1) = 0
x = 1, 3
y = 4(1) + 1 = 5
y = 4(3) + 1 = 13
Two solutions: (1,5) (3,13)