Find the derivative of the following functions by first expanding or simplifying the expression. Simplify your answers. 
y = (x² - 2ax + a²) / (x - a); a is a constant.

Verified step by step guidance

1. Step 1: Recognize that the function y = \frac{x^2 - 2ax + a^2}{x - a} is a rational function, which can be simplified by performing polynomial long division or by recognizing it as a special form.
2. Step 2: Notice that the numerator x^2 - 2ax + a^2 can be rewritten as (x - a)^2 by recognizing it as a perfect square trinomial.
3. Step 3: Simplify the expression by canceling the common factor (x - a) in the numerator and the denominator, resulting in y = x - a.
4. Step 4: Differentiate the simplified function y = x - a with respect to x. Since a is a constant, the derivative of a constant is zero.
5. Step 5: Apply the basic differentiation rule: the derivative of x with respect to x is 1. Therefore, the derivative of y = x - a is y' = 1.