Solution - Linear equations with two unknowns

System of Linear Equations entered :

   [1]    x + 5y = 1
   [2]    2x + 7y = -1

Graphic Representation of the Equations :

    5y + x = 1        7y + 2x = -1  

  
 

Solve by Substitution :

// Solve equation [1] for the variable  x 
 

  [1]    x = -5y + 1

// Plug this in for variable  x  in equation [2]

   [2]    2•(-5y+1) + 7y = -1
   [2]     - 3y = -3

// Solve equation [2] for the variable  y 

   [2]    3y = 3 

   [2]    y = 1 

// By now we know this much :

    x = -5y+1
    y = 1

// Use the  y  value to solve for  x 

    x = -5(1)+1 = -4 

Solution :

 {x,y} = {-4,1}