The lowest or highest point of a parabola is called the vertex.The x-coordinate of the vertex is found using the formula x = .To find the y-coordinate of the vertex, substitute the x-coordinate into the equation and solve for y.The axis of symmetryof a parabola is also found using the formula x = .Domain is the set of all possible x-values for an equation.Range is the set of all possible y-values for an equation.The average rate of change is calculated by dividing the change in the y-values by the change in the x-values.f(x + k) shifts the graph left if k > 0 and right if k < 0.f(x) + k shifts the graph up if k > 0 and down if k < 0f(kx) makes the parabola wider if 0 < |k| < 1, and narrower if |k| > 1. If k is negative, the parabola will open downward.Remember that f(x) and y are interchangeable.Completing the SquareBe sure that the equation is equal to f(x) or equal to zero.