## Geometry: Common Core (15th Edition)

$r^2-2r+1$
We start with the given expression: $(r-1)^2$ To simplify an algebraic expression, we must eliminate any parentheses and combine like terms. We expand the squared term:$(r-1)(r-1)$ We apply the distributive property to multiply the binomials: $r^2-r-r+1$ We combine the like terms by subtracting: $r^2-2r+1$