一元二次方程中,分母含有未知数,这种题怎么解啊?

问题描述:

一元二次方程中,分母含有未知数,这种题怎么解啊?
(4x/x²+x+3) + 5x/x²-5x+3= - 3/2

(4x/x²+x+3) + 5x/x²-5x+3= - 3/2 (先分子分母相约)
(4/x+x+3) + 5/x-5x+3= - 3/2 (再去分母,即等式两边同乘以2x)
8+2x²+6x+10-10x²+6x=-3x (移项、未知数的系数取正数,再合并)
8x²-15x-18=0
再用求根公式求解== 那个,貌似好像是我打的式子出了点问题4x/(x²+x+3) +5x/(x²-5x+3)= - 3/2 请见谅,能不能重新解释下题目?4x/(x²+x+3)+ 5x/(x²-5x+3)= - 3/2 x{4/(x²+x+3)+ 5/[(x²+x+3)-6x]}= - 3/2 令x²+x+3=y,则原式化为:x[4/y+5/(y-6x)]=-3/2等式两边同乘以2y(y-6x)2x[4(y-6x)+5y]=-3y(y-6x)2x(9y-24x)=-3y(y-6x)18xy-48x²=18xy-3y²48x²-3y²=0(4x)²-y²=0(4x+y)(4x-y)=04x+y=0或4x-y=0将x²+x+3=y代入4x+y=0得:4x+x²+x+3=0x²+5x+3=0 x²+2*(5/2)x+(5/2)²+3-25/4=0(x+5/2)²=13/2²x=√13/2-5/2=(√13-5)/2或x=-√13/2-5/2=(-√13-5)/2将x²+x+3=y代入4x-y=0得:4x-x²-x-3=0x²-3x+3=0x²-2*(3/2)x+(3/2)²-9/4+3=0(x-3/2)²=3/2²x=3/2±√3/2=(3±√3)/2