if n is such that 36 <= n <= 72

then x=(n^2 + 2(n(n+4))^1/2+16)/(n+4(n+4)^1/2) satisfies:

1) 20 < x < 54
2) 23 < x < 58
3) 25 < x < 64
4) 28 < x < 60

Can anyone give me some pointers for solving the above problem. So taht I can go ahead with the same.

Thanks,