If 5+u=5 then what is u

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

What is the solution to the system of equation graphed belowa.(0,-4)b.(2,5),1),-3)

Rick is driving to his uncles house in greenville, which is 120 miles from ricks town .after covering x miles rick she's a sign stating that greensville is 20 miles away. which equation when solved will give the value of x. a: x+120 = 20 b: x x120 =20 c: x +20 equals 120 d: x x20= 120