Could someone help me with this? I am super desperate and I don’t understand this math at all. “Adding which terms to 3x^2y would result in a monomial? Check all that apply.”
•3xy
•-12x^2y
•2x^2y^2
•7xy^2
•-10x^2
•4x^2y
•3x^3
Here’s a picture in case I wrote something weird, lol (it should be at the top and it looks all black but the question shows up once you click on it.)

Assume that there is a 11% rate of disk drive failure in a year. a. if all your computer data is stored on a hard disk drive with a copy stored on a second hard disk drive, what is the probability that during a year, you can avoid catastrophe with at least one working drive? b. if copies of all your computer data are stored on four independent hard disk drives, what is the probability that during a year, you can avoid catastrophe with at least one working drive?