Löse die folgenden biquadratischen Gleichungen ax4 + bx2 + c = 0

-10x4 - 40x2 + 600 = 0
 x1 = 2.45  x2 = -2.45
x3 = ◊  x4 = ◊		-7.5x4 + 120 = 0
 x1 = ◊  x2 = ◊
x3 = 2  x4 = -2
-2x4 - 2x2 + 4 = 0
 x1 = 1  x2 = -1
x3 = ◊  x4 = ◊		x4 - 13x2 + 30 = 0
 x1 = 3.16  x2 = -3.16
x3 = 1.73  x4 = -1.73
-9.5x4 + 47.5x2 = 0
 x1 = 2.24  x2 = -2.24
x3 = 0  x4 = 0		-7.5x4 - 90x2 - 150 = 0
 x1 = ◊  x2 = ◊
x3 = ◊  x4 = ◊
-9.5x4 + 57x2 + 152 = 0
 x1 = ◊  x2 = ◊
x3 = 2.83  x4 = -2.83		-6x4 + 54 = 0
 x1 = 1.73  x2 = -1.73
x3 = ◊  x4 = ◊
2.5x4 - 42.5x2 + 180 = 0
 x1 = 3  x2 = -3
x3 = 2.83  x4 = -2.83		9.5x4 - 66.5x2 - 171 = 0
 x1 = 3  x2 = -3
x3 = ◊  x4 = ◊
3.5x4 + 3.5x2 - 21 = 0
 x1 = 1.41  x2 = -1.41
x3 = ◊  x4 = ◊		-3.5x4 + 28x2 + 70 = 0
 x1 = ◊  x2 = ◊
x3 = 3.16  x4 = -3.16
5x4 - 10x2 - 40 = 0
 x1 = ◊  x2 = ◊
x3 = 2  x4 = -2		-3x4 + 75 = 0
 x1 = 2.24  x2 = -2.24
x3 = ◊  x4 = ◊
-7x4 - 63x2 - 126 = 0
 x1 = ◊  x2 = ◊
x3 = ◊  x4 = ◊		-9.5x4 - 38x2 + 199.5 = 0
 x1 = ◊  x2 = ◊
x3 = 1.73  x4 = -1.73
2x4 + 20x2 + 50 = 0
 x1 = ◊  x2 = ◊
x3 = ◊  x4 = ◊		-6.5x4 + 19.5x2 + 455 = 0
 x1 = 3.16  x2 = -3.16
x3 = ◊  x4 = ◊
x4 - 10x2 + 21 = 0
 x1 = 2.65  x2 = -2.65
x3 = 1.73  x4 = -1.73		-9x4 + 72x2 - 108 = 0
 x1 = 2.45  x2 = -2.45
x3 = 1.41  x4 = -1.41