Solve the system using either Gaussian elimination with back

Solve the system using either Gaussian elimination with back-substitution or Gauss-Jordan elimination. (If there is no solution, enter NO SOLUTION. If the system has an infinite number of solutions, set y = t and solve for x in terms of t.) 3x + 6 y = 21 -3x -6y = -21 (x, y) = (7 - 0t, t)

Solution

The given system is equivalent to (just ) one equation

          x+2y=7 or x =7-2y

So it has infinitely many solutions parametrized by (7-2t,t)