f.4 differentiation

1. If y=(2x^2+1)^3/x,find the second derivatives when x=1.
the ans. is 234.

2. If f(x)=e^2x/x^(1/2).find the value of f "(4)
the ans is 227e^8/128

3. If y =(x^2+4)^(-3),show that (x^2+4)y"+8x(y')+6y=0

Please show clear steps for the 3 questions. thx