1. Let's clarify the problem: you want to understand how the expression $-x - y$ is obtained. 2. The expression $-x - y$ means the negative of $x$ minus $y$. This can come from distributing a negative sign or combining terms. 3. For example, if you start with $-(x + y)$, applying the distributive property gives: $$-(x + y) = -1 \times x + (-1) \times y = -x - y$$ 4. This shows that the negative sign outside the parentheses changes the signs of both $x$ and $y$ inside. 5. Another way to see it: if you have $-x - y$, it is the same as $-(x) - y$, which is just subtracting $x$ and $y$ separately. 6. So, the key rule is the distributive property of multiplication over addition: $$a(b + c) = ab + ac$$ 7. When $a = -1$, it flips the signs inside the parentheses. 8. Therefore, $-(x + y) = -x - y$. This is how you get the expression $-x - y$.