Answer
$y^2-2y-3$
Work Step by Step
We start with the given expression: $(y+1)(y-3)$
To simplify an algebraic expression, we must eliminate any parentheses and combine like terms.
We apply the distributive property to multiply the binomials: $y^2+y-3y-3$
We combine the like terms by subtracting: $y^2-2y-3$
