设ax²+bx+c=0(a≠0)的两根分别为x1,x2
则有, ax1²+bx1+c=0 且 ax2²+bx2+c=0
两根之和为s1,两根的平房和为s2,两根的立方和为s3,
即s1=x1+x2 s2=x1²+s2² s3=x1³+x2³
as3+bs2+cs1
= a(x1³+x2³)+b(x1²+s2²)+c(x1+x2)
= x1(ax1²+bx1+c)+ x2(ax2²+bx2+c)
= x1*0 +x2*0
= 0
设ax²+bx+c=0(a≠0)的两根分别为x1,x2
则有, ax1²+bx1+c=0 且 ax2²+bx2+c=0
两根之和为s1,两根的平房和为s2,两根的立方和为s3,
即s1=x1+x2 s2=x1²+s2² s3=x1³+x2³
as3+bs2+cs1
= a(x1³+x2³)+b(x1²+s2²)+c(x1+x2)
= x1(ax1²+bx1+c)+ x2(ax2²+bx2+c)
= x1*0 +x2*0
= 0