The following system of linear equations
7x + 6y – 2z = 0
3x + 4y + 2z = 0
x – 2y – 6z = 0, has
(1) infinitely many solutions, (x, y, z) satisfying x = 2z
(2) no solution
(3) only the trivial solution
(4) infinitely many solutions, (x, y, z) satisfying y = 2z