一元二次方程根的判别式是初中数学学习的的重点,是重要的基础知识,也是解数学题的重要工具.它能用于判定方程根的情况,证明二次三项式为完全平方式,利用其构造一元二次方程,进行代数恒等式或不等式的证明;与几何知识相联系时,还可以解决判断三角形的形状;解决二次函数相关问题等.本文列举几种常见的题型及解法,供读者学习参考. The discriminant of the quadratic equation root is the key point of junior mathematics learning. It is an important basic knowledge and an important tool for solving mathematics problems. It can be used to determine the root of the equation and prove that the quadratic trinomial is completely flat. Use it to construct a unitary quadratic equation to prove the algebraic identity or inequality; when it relates to geometry knowledge, it can also solve the problem of determining the shape of a triangle; solve quadratic function related problems, etc. This article lists several common questions and solutions. For readers to learn reference.