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