x1 x2是方程3x2-7x+2=0两根求x1-x2

x1 x2是方程3x2-7x+2=0两根求x1-x2
x1 x2是方程3x2-7x+2=0两根求x1-x2

x1 x2是方程3x2-7x+2=0两根求x1-x2
（3x-1）(x-2)=0 x1=2 x2=1/3 x1-x2=5/3

3x^2-7x+2=0
(3x-1)(x-2)=0
x1=1/3 x2=2

x1 x2是方程3x2-7x+2=(3x-1)(x-2)=0两根
=>x1+x2=7/3,x1x2=2/3
=>(x1-x2)^2=(x1+x2)^2-4x1x2=49/9-8/3=25/9
=>x1-x2=± 5/3