To get rid of the absolute value bars you have to get two different equations which would be 2x+4>-8 AND 2x+4>8. Pay attention to the signs, if there is greater than or equal to then it would have a line underneath the sign, which neither of the equations should have since you haven't moved a negative. solve normally and you'll get -6 blank circle and 2 blank circle.
the mean would be appropriate measure of center to describe the data shown in the histogram because the data is symmetrical.A symmetric histogram is a distribution in which the 2 halves appear to be the same on both sides.