Answer
$H'(u)=2u-1$
Work Step by Step
$H(u)=(u-\sqrt{u})(u+\sqrt{u})$
Using the difference of two squares factorization formula, which is:
$a^{2}-b^{2}=(a-b)(a+b)$
We can write the function like this:
$H(u)=(u-\sqrt{u})(u+\sqrt{u})=u^{2}-(\sqrt{u})^{2}=u^{2}-u$
Now, differentiate each term:
$H'(u)=2u-1$
