如果二次方程有两个不等实根,则判别式△＞0
即
(2m-3)^2-4m^2＞0
(2m-3-2m)(2m-3+2m)＞0
-3（4m-3)＞0
而-3＜0,∴4m-3＜0
→m＜3/4