第1个回答 2015-08-28
3x^2-|x|-4=0
case 1: x>0
3x^2-x-4=0
(3x-4)(x+1) =0
x=4/3 or -1
solution for case 1: x=4/3
case 2: x<0
3x^2+x-4=0
(3x+4)(x-1) =0
x=-4/3 or 1
solution for case 2: x=-4/3
x1+x2= 8/3
x1.x2=-16/9
(x1+x2-1)/(x1x2)
=(8/3-1)/(-16/9)
=(5/3)(-9/16)
=-15/16