Question

已知一元二次方程2x^2-3x+1=0的两个根分别为x1 x2

求x1^2+x2^2和(x1-x2)^2

Answer 1

x1+x2=3/2
x1x2=1/2
所以x1²+x2²
=(x1+x2)²-2x1x2
=9/4-1
=5/4

(x1-x2)²
=(x1+x2)²-4x1x2
=9/4-2
=1/4

Answer 2

你把它套公式解一下
x1=1 x2=1/2
带入x1^2+x2^2=1+1/4=5/4
(x1-x2)^2=1/4
望采纳

Answer 3

2和4