PLEASE HELP ME find x ​

The standard deviation for a set of data is 5.5. the mean is 265. what is the margin of error?

Write the component forms of vectors u and v, shown in the graph, and find v − 2u. u= (< -3, -2> , < -3, -1> , < -2, -2> , < -2, -1> ) v= (< -5, 1> , -4, 0> , < 0, -4> , < 1, -5> ) v-2u= (< 5, 3> , < 0, 4> , < 4, 0> , < 5, -3>

What is the midpoint of np if n (1,9) and p (-5-1)