Ecuaciones de 2do grado

3x² -36x +105 = 0
x² -6x = 0
x² -36 = 0
-x² -3x -2 = 0
-2x² -6x +20 = 0
3x² +42x +135 = 0
-2x² -12x +14 = 0
-x² +23x -90 = 0
2x² -10x -72 = 0
3x² -21x = 0
-2x² -34x -140 = 0