Gives a function (x) and numbers L, c, and > 0. In each case, find an open interval about c on which the inequality

Gives a function ƒ(x) and numbers L, c, and ϵ > 0. In each case, find an open interval about c on which the inequality |ƒ(x) - L | < ϵ holds. Then give a value for δ > 0 such that for all x satisfying 0 < |x - c| < δ the inequality |ƒ(x) - L | < ϵ holds.

f(x) = x - 7, L = 4, C = 23, E = 1