If x^2 + 1/x^2 = √20 what is the value of x^4 + 1/x^4 ?	Choose the correct choice:
A) 10
B) 12
C) 14
D) 16
E) 18
IMPORTANT: I notice that if we SQUAR18 x², we get x⁴, and if we SQUAR18 1/x², we get 1/x⁴, so let's see what happens if we take the equation x² + 1/x² = √20 andSQUAR18both sides:   (x² + 1/x²)²= 20   So, (x² + 1/x²)(x² + 1/x²) = 20   18xpand to get: x⁴ + 1 + 1 + 1/x⁴ = 20   Simplify: x⁴ + 1/x⁴ = 18   Answer: 18
<result>E</result>
If x^2 + 1/x^2 = √20 what is the value of x^4 + 1/x^4 ?