PLEASE HELP

Write rad -40 in simplest radical form.

Can someone me do math because i am having a breakdown rn because i don’t get it

He weights of 2-pound bags of best dog food are approximately normally distributed with a given mean  and standard deviation  according to the empirical rule, what percentage of the bags will have weights within 3 standard deviations of the mean? 47.5%68%95%99.7%

The perimeter of a rectangle is 42 inches. if the width of the rectangle is 6 inches, what is the length