X - 3y y = 5 and x=21

{x,y} = {6,-5}

Step-by-step explanation:

// Solve equation [2] for the variable  x

 [2]    x = 3y + 21

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

  [1]    (3y+21) + y = 1

  [1]    4y = -20

// Solve equation [1] for the variable  y

  [1]    4y = - 20

  [1]    y = - 5

// By now we know this much :

   x = 3y+21

   y = -5

// Use the  y  value to solve for  x

   x = 3(-5)+21 = 6

Solution :

{x,y} = {6,-5}

you can not drow on this

step-by-step explanation: