/ 4\ | -6 + 6*x | lim |-1 + ---------| x->1+\ x /
Limit(-1 + (-6 + 6*x^4)/x, x, 1)
-1
= -1
/ 4\ | -6 + 6*x | lim |-1 + ---------| x->1-\ x /
-1.0