Answer:
r³ + 15r² - 10r - 4
Step-by-step explanation:
First, note you can remove the brackets, in this case they contribute nothing at all.
Then, group the like terms and add them, e.g., we have 3r³ and -2r², they add up to r³.
Finally, order them from greatest power of r to smallest power of r.
That's all!
