Solution - Linear equations with two unknowns

System of Linear Equations entered :

   [1]    x + y = -1
   [2]    x - y = 5

Graphic Representation of the Equations :

    y + x = -1        y + x = 5  

  
 

Solve by Substitution :

// Solve equation [2] for the variable  x 
 

  [2]    x = y + 5

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

   [1]    (y +5) + y = -1
   [1]    2y = -6

// Solve equation [1] for the variable  y 

   [1]    2y = - 6 

   [1]    y = - 3 

// By now we know this much :

    x = y+5
    y = -3

// Use the  y  value to solve for  x 

    x = (-3)+5 = 2 

Solution :

 {x,y} = {2,-3}