x^2-3x+1=0 2x^2+6=7x 3x^2-9x+2=0
问题描述：
x^2-3x+1=0 2x^2+6=7x 3x^2-9x+2=0
答
x^2-3x+1=0
(x-3/2)^2-9/4+1=0
(x-3/2)^2=5/4
x-3/2=±1/2√5
x=(3±√5)/2
2x^2+6=7x
2x^2-7x+6=0
(2x-3)(x-2)=0
x1=3/2 x2=2
3x^2-9x+2=0
x^2-3x+2/3=0
(x-3/2)^2=9/4-2/3=27/12-8/12=19/12
x-3/2=±1/6√57
x=3/2±1/6√57