4x^2 + 9x = 04x^2 + 9x = 0x(4x + 9) = 0x = 0, -9/4
9x^2 - 4 = 09x^2 - 4 = 0(3x - 2)(3x + 2) = 0x = 2/3, -2/3
-5x^2 + 23x + 10 = 0-5x^2 + 23x + 10 = 0(-5x - 2)(x - 5) = 0x = -2/5, 5
4x^2 + 9x = 0
4x^2 + 9x = 0
x(4x + 9) = 0
x = 0, -9/4
9x^2 - 4 = 0
9x^2 - 4 = 0
(3x - 2)(3x + 2) = 0
x = 2/3, -2/3
-5x^2 + 23x + 10 = 0
-5x^2 + 23x + 10 = 0
(-5x - 2)(x - 5) = 0
x = -2/5, 5