Wenzhe Sheng

Undergraduate researcher at Peking University, School of Earth and Space Sciences.

（15）已知方程 $

x - a

x^2 - 2ax + a^2 + 2a - 3

x - 1

x - 2

$ 恰有4个不同的实数解，则正实数$a$的取值范围是______。