Evaluating limits

Question

Find  . You must show your work or explain your work in words.

Answer 1

, for x < 4 x - 4 < 0 and Ιx - 4Ι = - (x - 4) and because = lim (-(x - 4))/(x - 4) = -1 x→ 4^-

Answer 2

As long as x <4, the given fraction is equal to -1 and the limit from the left is -1.

Note that the limit from the right is +1, so that the function has a non-removable discontinuity at x = 4 (and is undefined at x=4).