∵ m x ² - m x + 1 = 0 有两个相等的实数根
∴ △ = b ² - 4 a c = 0
即 (- m)² - 4 m × 1 = 0
m ² - 4 m = 0
m(m - 4)= 0
m = 0 或 m - 4 = 0
m = 0 或 m = 4
∵ m = 0 时方程无意义
∴ m = 4
∵ m x ² - m x + 1 = 0 有两个相等的实数根
∴ △ = b ² - 4 a c = 0
即 (- m)² - 4 m × 1 = 0
m ² - 4 m = 0
m(m - 4)= 0
m = 0 或 m - 4 = 0
m = 0 或 m = 4
∵ m = 0 时方程无意义
∴ m = 4