Ecuaciones de 2do grado

2x² -26x +84 = 0
-x² +3x +40 = 0
2x² +4x -96 = 0
-x² +3x +28 = 0
x² +11x +18 = 0
-2x² +18x -28 = 0
2x² +8x -64 = 0
x² -8x +15 = 0
x² +x -6 = 0
-x² +10x -21 = 0
x² -2x -48 = 0