Find the x-value of the relative minima of the function:

2x^(2)+((256)/(x))+8

y = 2x^2 + 256/x + 8

y' = 4x - 256/x^2 = (4x^3 - 256)/x^2
Since y is not defined for x=0, y'=0 when

4x^3 = 256
x = 4