Question

solve the following system of linear equation graphically
x-y=1
2x+y=8

Answer 1

System of Linear Equations entered :

  [1] x - y = 1   [2] 2x + y = 8

Graphic Representation of the Equations :

y + x = 1 y + 2x = 8

Solve by Substitution :

// Solve equation [2] for the variable  y  
 

[2] y = -2x + 8

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

  [1] x - (-2x+8) = 1   [1] 3x = 9

// Solve equation [1] for the variable  x  

  [1] 3x = 9    [1] x = 3 

// By now we know this much :

  x = 3   y = -2x+8

// Use the  x  value to solve for  y  

  y = -2(3)+8 = 2 

Solution :

 {x,y} = {3,2}