(-2,-1) when you reflect over the x-axis, the number of units from side to side remain the same. However, the point moves the same number of units under the x-axis as it was above it. It was 1 above it so now it is 1 below it.
If you reflect the point H which is (-2,1) over the x-axis then you would move point H to the x axis line which is one point down, then you would move the point negative one down again over the x axis so the point h1 would be (-2,-1) because it's one away from the X axis if you reflected it
