Square root of 6 - square root of 6 + square root of 6

The mean temperature for the first 4 days in january was 7°c. the mean temperature for the first 5 days in january was 5°c. what was the temperature on the 5th day?

Adrawer contains 12 identical white socks, 18 identical black socks and 14 identical brown socks. what is the least number of socks you must choose, without looking, to be certain that you have chosen two socks of the same colour?

Simplify. (-2)^-3 a. -8 b. -1/8 c. 1/8 d. 8