Answer:
√a(√a + 2) a - 2√a
----------------- = -----------------
a - 4 a - 4
Explanation:
I am assuming that by "sqrt(a)/sqrt(a)-2" you meant:
√a
----------
√a - 2
To rationalize the denom., multiply numerator and denom. of this fraction by the conjugate of √a - 2, which is √a + 2:
√a(√a + 2)
-----------------
a - 4