<p>Oh god. I guess you haven’t taken calculus.</p>
<p>The link you provided in #9 is basic differentiation with polynomials. It works for this question too, you just have to distribute first.</p>
<p>I used the product rule.
[Product</a> Rule, Quotient Rule, and Chain Rule Tutorial](<a href=“http://www.1728.org/chainrul.htm]Product”>Product Rule, Quotient Rule, and Chain Rule Tutorial)</p>