Given that 4x^2-32x-20+k is a perfect square find k​

Which statement most accurately describe why the division property of exponents does not apply to the expression (-8)^2/(-3)^4

Twelve less than a number is at most 20

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?