Final answer:
To simplify -2√20-√125, simplify each square root separately. √20 becomes 2√5 and √125 becomes 5√5. Substituting these values, the expression simplifies to -9√5.
Step-by-step explanation:
To simplify -2√20-√125, we need to simplify each square root separately. First, let's simplify √20. Since 20 is a perfect square, we can write it as √(4 * 5). This becomes 2√5. Next, let's simplify √125. Since 125 is also a perfect square, we can write it as √(25 * 5). This becomes 5√5.
Now, we can substitute the simplified square roots into the original expression: -2√20 - √125 = -2(2√5) - 5√5 = -4√5 - 5√5 = (-4 - 5)√5 = -9√5.
Therefore, -2√20-√125 simplifies to -9√5.
Learn more about simplifying square roots