The problem shows the graph of f(x) = x^2 - 1 and asks to find δ such that if 0 < |x - 2| < δ, then |f(x) - 3| < 0.2.
This is in the first chapter of my calculus book and dealing strictly with limits but I don't know how to do the problem, anyone want to chime in?
As a retired chair of a university mathematics department, I advise you to do a good course in Pre-Calculus.
You need a good review of the properties of absolute value and inequalities. I suspect you could benefit in many more ways from such a course.