Solution - Linear equations with two unknowns

System of Linear Equations entered :

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

Graphic Representation of the Equations :

    y + x = 1        -2y + x = 4  

  
 

Solve by Substitution :

// Solve equation [2] for the variable  x 
 

  [2]    x = 2y + 4

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

   [1]    (2y+4) - y = 1
   [1]    y = -3

// Solve equation [1] for the variable  y 

   [1]    y = - 3 

// By now we know this much :

    x = 2y+4
    y = -3

// Use the  y  value to solve for  x 

    x = 2(-3)+4 = -2 

Solution :

 {x,y} = {-2,-3}