(algebra) A mathematical equation in which one or both sides is an algebraic expression, such as 2x + 7y = 3.

(algebra) Any algebraic equation in which one or both sides are in the form of a polynomial.

(chemistry) a symbolic representation of a chemical reaction; reactants are represented on the left, and products on the right

(number theory) The Diophantine equation x²-my²=1 for a given integer m, to be solved in integers x and y.

(astronomy, celestial mechanics) the mathematical relationship between the mean anomaly (M) and the eccentric anomaly (E) of a planet in an elliptical orbit with eccentricity (𝜀). M=E-𝜀· sin (E).

(mathematics) a set of equations of motion of a mechanical system which relate the kinetic energy of the system to its generalized coordinates

(chemistry) An equation which approximates the dependence of the rate of any chemical reaction on the temperature.

(calculus) an equation involving the derivatives of a function

(mathematics) a polynomial equation of the second degree.

(mathematics, physics, potential theory) The partial differential equation (∂²𝜑)/(∂x_1²)+(∂²𝜑)/(∂x_2²)+⋯+(∂²𝜑)/(∂x_n²)=0, commonly written 𝛥𝜑=0 or ∇²𝜑=0, where 𝛥(=∇²) is the Laplace operator and 𝜑 is a scalar function.