Answer
$$y^2 - 2y + 1$$
Work Step by Step
First, we want to expand the expression so we can clearly see all the terms:
$$(y - 1)(y - 1)$$
We now use the FOIL method of multiplying the two binomials. We multiply the first terms, the outer terms, the inner terms, and then the last terms to get:
$$y^2 - y - y + 1$$
We combine like terms to simplify the expression:
$$y^2 - 2y + 1$$
