when x < -6, x + 6 is negative. So, l x + 6 l = -(x + 6)
when x > -6, x + 6 is positive. So, l x + 6 l = x + 6
Take "one'sided" limits:
limx→--6- [(2x + 12) / l x+6l] = limx→-6- [2(x+6) / -(x+6)] = -2
limx→-6+ [(2x+12) / lx + 6l] = limx→-6+ [2(x+6) / (x+6)] = 2
Since the one-sided limits are unequal, limx→-6 [(2x+12) / lx+6l] does not exist.