The complete solution of the inequation x2-4x<12 is
x<-2 or x>6
-6<x<2
2<x<6
-2<x<6
x2-4x<12
⇒x2-4x-12<0⇒x2-6x+2x-12<0
⇒(x-6)(x+2)<0⇒-2<x<6.