In polygon FGHJ, what is the length of HJ if H is at (-3, 5) and J is at (-3, -1)?

What is the standard deviation of the following data set rounded to the nearest tenth? 3, 17, 18, 15, 12, 21, 9

On a piece of paper graph f(x)=5•(0.4)^x

To describe a sequence of transformations that maps triangle abc onto triangle a"b"c", a student starts with a reflection over the x-axis. how should the student complete the sequence of transformations to map triangle abc onto triangle a"b"c"? plz