I've been asking this for an hour plss heeelp asap​

The mean of a set of data is -3.82 and its standard deviation is 2.31. find the z score for a value of 3.99.

Aheated piece of metal cools according to the function c(x) = (.5)x ? 7, where x is measured in hours. a device is added that aids in cooling according to the function h(x) = ? x ? 2. what will be the temperature of the metal after two hours?

Valentina is subtracting from . she finds the lcd to be 15y2. what is valentina's next step?