(2x+3y)+(4x+9y) how do i simplify it

Which equation matches the graph shown ?

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.

Abox holds 500 paperclips. after a week on the teacher's desk 239 paperclips remained. how many paperclips were used?