We need to simplify the two brackets separately first:
(x)³ = x³
(-x³y)² = - The x becomes to the power of six because when you have a power to a power we need to multiply the powers together so, 3 times 2 is 6. Because there is no power on the y we say it is to the power of 1 so, 1 times 2 is 2.
Now we multiply the two brackets together:
=
We add the powers for multiplication so it is to the power of 9 for x and because there isn't a second y term we leave y as it is. The x is negative because a negative multiplied by a positive term is a negative term.