Question

Use the parabola tool to graph the quadratic function f(x)=−(x−3)(x+1).

Graph the parabola by first plotting its vertex and then plotting a second point on the parabola.

Answer 1

The parabola has roots at x=3 and x=-1, so its vertex is halfway between those points, at x=1, and so the y-coordinate of the vertex is -(1-3)(1+1)=4.

Another point that lies on the parabola is (-1, 0).