All useful formulae

Linear function: slope-intercept form

Linear function: general form

Quadratic function

Quadratic function: vertex form, where (h,k) is the vertex

Quadratic formula

Discriminant for a quadratic

Axis of symmetry for a quadratic

Sum of roots of a quadratic

Product of roots of a quadratic

Exponential function

Circle relation, where (h,k) is the centre and r is the radius

Percent change, where x1 is the initial value and x2 is the final value