y = -6x + 2 . . . . . . . . equation (1)
-12x - 2y = -4 . . . . . . equation (2)
substitute (1) into (2),
-12x - 2(-6x + 2) = -4
-12x + 12x - 4 = -4
-4 = -4
Both sides are same. If we arrive at a statement that is true, then the system has infinite number of solution.
So there are infinite number of solutions for system of equations
y=-6x + 2 and -12x - 2y=-4