Answer:
-3 + 10y
Explanation:
Apply the distributive property. Think of the negative outside the parentheses as -1. Multiply each term inside the parentheses by -1. What that does is change each sign inside the parentheses.
-(3 - 10y) = -1 * (3 - 10y) = -1 * 3 - 1 * (-10y) = -3 + 10y