Root formula: x

=-b radical b? -4ac/2a

General form: ax? +bx+c

Parabola: y=a(x-h)? +k

Intersection point: d < r

Tangency: d=r

Separation: d > r

Vertex: (-b/2a, 4ac-b? /4a)

Second: products

X 1X2=-b/a

and

X 1+X2c/a

Sum of polygon interior angles: (n-2)* 180