Replace MathJax with MathML (#2477)

Signed-off-by: Daniel Gray <dngray@privacyguides.org>

docs/android.md

@@ -202,7 +202,18 @@ A few more tips for purchasing a Google Pixel:
 - If you're after a bargain on a Pixel device, we suggest buying an "**a**" model, just after the next flagship is released. Discounts are usually available because Google will be trying to clear their stock.
 - Consider price beating options and specials offered at physical stores.
 - Look at online community bargain sites in your country. These can alert you to good sales.
-- Google provides a list showing the [support cycle](https://support.google.com/nexus/answer/4457705) for each one of their devices. The price per day for a device can be calculated as: $\text{Cost} \over \text {EOL Date}-\text{Current Date}$, meaning that the longer use of the device the lower cost per day.
+- Google provides a list showing the [support cycle](https://support.google.com/nexus/answer/4457705) for each one of their devices. The price per day for a device can be calculated as:
+    <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline" class="tml-display" style="display:inline math;">
+      <mfrac>
+        <mtext>Cost</mtext>
+        <mrow>
+          <mtext>End of Life Date</mtext>
+          <mo>−</mo>
+          <mtext>Current Date</mtext>
+        </mrow>
+      </mfrac>
+    </math>
+    , meaning that the longer use of the device the lower cost per day.
 - If the Pixel is unavailable in your region, the [NitroPhone](https://shop.nitrokey.com/shop) can be shipped globally.
 
 ## General Apps