Respuesta :

Answer:  " 4x + 2xy - 7pq " .
___________________________________
Explanation:
___________________________________
Given:  
4x - 7xy + 9xy - 7pq " ;  Simplify the expression;
___________________________________
  Combine the "like terms:
___________________________________
       -7xy + 9xy = 2xy ;
___________________________________
Now, rerewrite the expression, substituting the "-7xy + 9xy";  with " + 2xy" ;
___________________________________
   
→ " 4x + 2xy - 7pq " .
___________________________________