这里所说的“逆”是指一元二次方程根与系数关系的逆命题.设一元二次方程ax~2+bx+c=0(a≠0)的两个实数根为x_1、x_2,则x_1+x_2=-b/a,x_1x_2=c/a,这就是一元二次方程根与系数的关系.它的逆命题是:若实数x_1、x_2满足x_1+x_2=-b/a,x_1x_2=c/a,则x_1、x_2是一元二次方程ax~2+bx+c=0的两个实数根.我们把这个逆命题与一元二次方程根的判别式结合起来,可以解一些非一元二次方程的数学问题.下面举例说明: In this paper, “inverse ” refers to the inverse proposition of the relationship between the root of the quadratic equation and the coefficient.It is assumed that the two real roots of the quadratic equation ax ~ 2 + bx + c = 0 (a ≠ 0) x_2, then x_1 + x_2 = -b / a and x_1x_2 = c / a, which is the relationship between the root of the quadratic equation and the coefficient. The inverse of this equation is that if the real number x_1 and x_2 satisfy x_1 + x_2 = -b / a , x_1x_2 = c / a, then x_1 and x_2 are two real roots of the quadratic ax + 2 + bx + c = 0. We combine this inverse proposition with the discriminant of the root of the quadratic equation Some non-quadratic equations of mathematical problems. The following examples: