Ecuaciones de 2do grado

3x² -21x -54 = 0
-2x² -26x -60 = 0
3x² -42x +144 = 0
2x² +4x -70 = 0
2x² -2x -12 = 0
x² -2x = 0
-x² -8x +9 = 0
x² +x -30 = 0
-2x² -8x +120 = 0
x² -15x +50 = 0
-x² -8x -15 = 0