x(x+1)>112-5x,
x2+x>112-5x,
x2+6x-112>0,
(x-8)(x+14)>0.
So x-8 and x+14 must both be positive or both negative.
Therefore, x>8 and x>-14; or x<8 and x<-14.
Since 8>-14, it's sufficient that x>8; since -14<8 it's sufficient that x<-14.
SOLUTION: x>8 or x<-14.