What is the slope of this non-vertical line??

Which value is not a solution of 8x^3 – 1 = 0

Hi, can anyone show me how to do this problem? 100 points for this. in advance

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?