Evaluate 5a+ 4b2 when a = 7 and b = 6​

Factor completely. x^8 - 1/81 a) (x^4 + 1/9)(x^2 + 1/3)(x^2 - 1/3) b) (x^4 - 1/9)(x^2 + 1/3)(x^2 - 1/3) c) (x^4 + 1/9)(x^2 - 1/3)2

Complex numbers multiply √-4 * √-25 and show all intermediate steps. alternative notation is sqrt(-4) * sqrt(-25).

If your score on your next statistics test is converted to a z score, which of these z scores would you prefer: minus2.00, minus1.00, 0, 1.00, 2.00? why? a. the z score of 2.00 is most preferable because it is 2.00 standard deviations above the mean and would correspond to the highest of the five different possible test scores. b. the z score of 0 is most preferable because it corresponds to a test score equal to the mean. c. the z score of minus2.00 is most preferable because it is 2.00 standard deviations below the mean and would correspond to the highest of the five different possible test scores. d. the z score of minus1.00 is most preferable because it is 1.00 standard deviation below the mean and would correspond to an above average