一元二次方程ax~2+bx+c=0(a≠0)的两个根x_1,x_2与系数存在着某种特定的等式关系,即x_1+x_2=- b/a,x_1·x_2=c/a,我们把它称为韦达定理.我们遇到的数学问题中,并不是所有问题都能直接运用以上两个式子就能得到的,往往需要通过运用这两个式子的一些变形才能达到求解的目的.下面举例说明. The two roots x_1, x_2 of the quadratic equation ax ~ 2 + bx + c = 0 (a ≠ 0) have some specific relationship with the coefficients, ie x_1 + x_2 = - b / a, x_1 · x_2 = c / a, we call it the Veda’s Theorem. Of the mathematical problems we encounter, not all problems can be obtained by directly applying the above two formulas, and often we need to apply these two formulas Some deformation can be achieved for the purpose of solving.