Simonne used the following steps to simplify the given expression. 12 minus 3 (negative 2 x + 4)

Step 1: 12 + (negative 3) (negative 2 x) + (negative 3) (4)
Step 2: 12 + 6 x + (negative 12)
Step 3: 12 + (negative 12) + 6 x
Step 4: 0 + 6 x
Step 5: 6 x

What property of real numbers was used to transition from step 3 to step 4?

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?