This is a multi-step question, and i really don't know how to even start.

f(x) = x^2 - 4x + 1 if x <= 2 and ax + b if x > -2

Is differentiable at -2.

It is known that if a function is differentiable at a point 'c', then it is continuous at c. Using now the continuity of f at -2, we can establish a relationship between a and b. Find this relationship and express is in the form b = Aa + B, where A and B are constants.

This is the first part of the question, please help.