Given:
The system of equations that represent the constraints for the given situation is
 
 
 
 
To find:
The solution of given system of equations.
Solution:
We have, 
 ...(i)
           ...(i)
 ...(ii)
           ...(ii)
Multiply equation (i) by 4.
 ...(iii)
           ...(iii)
Subtracting (iii) from (ii), we get



Divide both sides by 12.90.


Put this value in (i).



The solution of system of equations is x=1.5 and y=2.75. It means, the yards of silk are 1.5 and yards of cotton are 2.75.
  
        
             
        
        
        
Answer:
If we use a graphing tool or a calculator, we can easily plot the equation provided. 
Please see the attached images, where we can find the center of the ellipse, the intercepts and more information about the graph.
 
        
             
        
        
        
The value of 4 in 704 is ones