[math]y = a(x-h)^2 +k[/math] is the vertex form of a quadratic equation. The vertex is the point [math](h, k)[/math] on the quadratic. The vertex is the minimum or maximum of the quadratic. [math]y = ax^2 + bx +c[/math] is the standard form of a quadratic equation. Move slider [math]a[/math]. See the width of the quadratic change. See the direction of the quadratic change when [math]a[/math] is a negative number. Positive [math]a[/math] give the quadratic a minimum point. Negative [math]a[/math] give the quadratic a maximum point. Move slider [math]h[/math]. See the horizontal position of the quadratic change. Positive [math]h[/math] values keep the minimum or maximum of the quadratic to the right of the [math]y[/math]-axis. Negative [math]h[/math] values keep the minimum or maximum of the quadratic to the left of the [math]y[/math]-axis. Move slider [math]k[/math]. See the vertical position of the quadratic change. Positive [math]k[/math] values keep the minimum or maximum of the quadratic above the [math]x[/math]-axis. Negative [math]k[/math] values keep the minimum or maximum of the quadratic above the [math]x[/math]-axis.