Show that 4x² - 12x + 9 = 0 has only one solution.

First method

4x² - 12x + 9 = 0

(2x - 3)² = 0

x = 3 / 2

Second method

4x² - 12x + 9 = 0

a = 4, b = -12 and c = 9

b² = 144

4ac = 144

b² = 4ac

-b / (2a) = 3 / 2