Raise 2/7 to a fraction with a denominator of 28

Simplify the expression and find the missing terms. the simplest form of has in the numerator and in the denominator.

Which system of linear inequalities is represented by the graph?

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?