Ex: If one line has a slope of 4, a line parallel to it will have a slope of 4. (h, k) is the vertex of the parabola. If a is positive, the parabola opens upward; if a is negative, the parabola opens downward. Median: Middle Term when Terms are In Order from Least to Greatest. the Mean is the Median is 4, and the Mode is 7, and the Range is 6.