How to find min max from lm
<p>I'm trying to figure out a way to find the minimum/maximum from a fitted quadratic model. In this case the minimum.</p>

<pre><code>x.lm &lt;- lm(Y ~ X + I(X^2))
</code></pre>

<p>Edit: To clarify, I can already find the minimum y through min(predict(x.lm)). How can I translate this to it's corresponding x value.</p>