how do you find the vertex using two points, when no equation is given and neither points are the vertex? what formula can i use to find it?
Vertex of what? A parabola?
Maybe this site will help:
http://www.algebra-class.com/vertex-formula.html
To find the vertex of a parabola using two points that are not the vertex and when no equation is given, you'll need to follow these steps:
1. Start by plotting the two given points on a graph.
2. Draw a straight line passing through these two points. This line is called the "axis of symmetry." The axis of symmetry is the vertical line that divides the parabola into two symmetrical halves.
3. Determine the midpoint of the line segment between the two given points. This midpoint will lie on the axis of symmetry.
4. Reflect the midpoint across the axis of symmetry to find the vertex. The vertex will lie on the axis of symmetry and will be equidistant from the two given points.
To summarize, the formula to find the vertex using two points when no equation is given would be:
1. Find the axis of symmetry by drawing a straight line through the two given points.
2. Locate the midpoint of the line segment between the two points; this gives you a point on the axis of symmetry.
3. Reflect the midpoint across the axis of symmetry to find the vertex.