I need help with this lol

If square root x = -7, then x= -49 true or false

Scores on the cognitive scale of the bayley-scales of infant and toddler development range from 1 to 19, with a standard deviation of 3. calculate the margin of error in estimating the true mean cognitive scale score, with 99% confidence, if there are 12 infants and toddlers in a sample.

Two numbers have a sum of -19. one number is x. what expression represents the other number?