Please someone help find the derivative?

Rewrite as follows:
y = (8 + x f(x)) / x^(1/2)
...= 8/x^(1/2) + x f(x)/x^(1/2)
...= 8x^(-1/2) + x^(1/2) f(x).

Differentiating (and using the product rule for the second term):
y' = 8 * (-1/2)x^(-3/2) + [(1/2) x^(-1/2) * f(x) + x^(1/2) * f '(x)]
...= -4x^(-3/2) + (1/2) x^(-1/2) * f(x) + x^(1/2) * f '(x).

I hope this helps!