Answer: 35
 the age of Roberto is x (x > 3)(x ∈ N)
because Roberto is 3 years older than Carolyn => the age of Carolyn is x - 3
in 7 years, the age of Roberto is x + 7; the age of Carolyn is x - 3 + 7 = x + 4
because  In 7 years the sum of their ages will be 81 => 
 x + 7 + x + 4 = 81
⇔ 2x + 11 = 81
⇔ 2x = 70
⇔ x = 70/2 = 35
=>  the age of Roberto is 35
Step-by-step explanation:
 
        
             
        
        
        
Answer:
  <em>= 279</em>
 <em>= 279</em> 
Step-by-step explanation:
 =
 =  + (n - 1)d
 + (n - 1)d 
d =  -
 -  
 
~~~~~~~~~ 
d = - 17 + 25 = - 9 + 17 = - 1 + 9 = 8 
 = - 25 + 8(39 - 1) = 279
 = - 25 + 8(39 - 1) = 279 
  <em>= 279</em><em> </em>
 <em>= 279</em><em> </em>
 
        
             
        
        
        
Answer:
27
Step-by-step explanation:
Given the expression

According to law of indices, this can be written as;

Hence the required answer is 27
 
        
             
        
        
        
Just divide 7/473 you should get your answer