Im bored any one wanna talk

What is the reflection image of (5,-3) across the line y = -x?

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

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.