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

-2x4 + 16x2 - 30 = 0
 x1 = 2.24  x2 = -2.24
x3 = 1.73  x4 = -1.73		8.5x4 + 25.5x2 - 459 = 0
 x1 = 2.45  x2 = -2.45
x3 = ◊  x4 = ◊
-2.5x4 + 10x2 + 30 = 0
 x1 = ◊  x2 = ◊
x3 = 2.45  x4 = -2.45		1.5x4 + 3x2 - 72 = 0
 x1 = 2.45  x2 = -2.45
x3 = ◊  x4 = ◊
2.5x4 - 25x2 = 0
 x1 = 0  x2 = 0
x3 = 3.16  x4 = -3.16		4x4 - 8x2 - 320 = 0
 x1 = 3.16  x2 = -3.16
x3 = ◊  x4 = ◊
-2x4 + 72 = 0
 x1 = 2.45  x2 = -2.45
x3 = ◊  x4 = ◊		-2x4 + 14x2 + 36 = 0
 x1 = ◊  x2 = ◊
x3 = 3  x4 = -3
7.5x4 - 45x2 = 0
 x1 = 0  x2 = 0
x3 = 2.45  x4 = -2.45		-7.5x4 - 30x2 + 337.5 = 0
 x1 = 2.24  x2 = -2.24
x3 = ◊  x4 = ◊
-10x4 + 100x2 - 160 = 0
 x1 = 1.41  x2 = -1.41
x3 = 2.83  x4 = -2.83		-10x4 + 100x2 - 90 = 0
 x1 = 3  x2 = -3
x3 = 1  x4 = -1
9.5x4 + 19x2 - 760 = 0
 x1 = ◊  x2 = ◊
x3 = 2.83  x4 = -2.83		-8.5x4 + 144.5x2 - 595 = 0
 x1 = 3.16  x2 = -3.16
x3 = 2.65  x4 = -2.65
7x4 + 35x2 + 42 = 0
 x1 = ◊  x2 = ◊
x3 = ◊  x4 = ◊		9.5x4 + 28.5x2 - 171 = 0
 x1 = 1.73  x2 = -1.73
x3 = ◊  x4 = ◊
-3.5x4 + 3.5x2 + 7 = 0
 x1 = 1.41  x2 = -1.41
x3 = ◊  x4 = ◊		-2x4 - 20x2 - 42 = 0
 x1 = ◊  x2 = ◊
x3 = ◊  x4 = ◊
-6x4 - 6x2 + 36 = 0
 x1 = ◊  x2 = ◊
x3 = 1.41  x4 = -1.41		x4 - 6x2 + 9 = 0
 x1 = 1.73  x2 = -1.73
x3 = 1.73  x4 = -1.73