How to factor out 2x^4 - 8x^2

2x⁴ - 8x²

common factor is 2x²

therefore, you need to divide everything by 2x²

2x ⁴ : 2x² = x²

8x² : 2x² = 4

2x² (x ²-4)

for x ²-4, you can also factor that using difference of squares

which is a ² - b² = (a+b) (a-b)

x²-4 = (x+2) (x-2)

final answer: 2x² (x+2) (x-2)