The formula of Vieta's theorem in high school mathematics is x 1+x2=-b÷a, and x 1x2 = c ÷ a Vieta's theorem explains the relationship between roots and coefficients in a quadratic equation with one variable. Through the inverse theorem of Vieta's theorem and the relationship between the sum and product of two numbers, a quadratic equation with one variable can be constructed.

David first discovered this relationship between the roots and coefficients of algebraic equations, so people called this relationship Vieta Theorem. Vieta's theorem plays a unique role in finding the symmetric function of roots, discussing the sign of roots of quadratic equations, solving symmetric equations and solving some conic problems.