Solution - Linear equations with two unknowns

System of Linear Equations entered :

   [1]    2x - y = 4
   [2]    x + 2y = 12

Graphic Representation of the Equations :

    y + 2x = 4        2y + x = 12  

  
 

Solve by Substitution :

// Solve equation [2] for the variable  x 
 

  [2]    x = -2y + 12

// Plug this in for variable  x  in equation [1]

   [1]    2•(-2y+12) - y = 4
   [1]     - 5y = -20

// Solve equation [1] for the variable  y 

   [1]    5y = 20 

   [1]    y = 4 

// By now we know this much :

    x = -2y+12
    y = 4

// Use the  y  value to solve for  x 

    x = -2(4)+12 = 4 

Solution :

 {x,y} = {4,4}