What is the answer and how to work it out

What is the distance between (–2 1/2,-3) and (1, –3)?

Find the zeros of the function. write the smaller solution first, and the larger solution second f(x)= (x+6)^2-49

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.