The origin of X in algebra. Why we say ‘how come’ for ‘why.’ Water handles.

<p>1144. This week, we look at the origin of the letter X as the variable for the unknown in algebra. Then, we look at the phrase "how come," explaining why it's more informal than "why" and how its grammar subtly differs from other question words.</p><p>That X segment was written by Peter Schumer, Professor of Mathematics and Natural Philosophy at Middlebury College, and <a href="https://theconversation.com/x-marks-the-unknown-in-algebra-but-xs-origins-are-a-math-mystery-210440">it originally appeared on The Conversation</a> and appears here through a Creative Commons license.</p><p><strong>Links to Get One Month Free of the Grammar Girl Patreon</strong> (different links for different levels)</p><ul><li>Order of the Snail ($1/month level): <a href="https://www.patreon.com/grammargirl/redeem/687E4" target="_blank">https://www.patreon.com/grammargirl/redeem/687E4</a></li><li>Order of the Aardvark ($5/month level): <a href="https://www.patreon.com/grammargirl/redeem/07205" target="_blank...