<exercise>
<statement>
<p>Explain why the matrix <m><xsl:value-of select="name"/>=<xsl:value-of select="matrix"/></m> is or is not invertible.</p>
</statement>
<answer>
<p><me>\operatorname{RREF}<xsl:value-of select="matrix"/>=<xsl:value-of select="rref"/></me></p>
<xsl:choose>
<xsl:when test="invertible"><m><xsl:value-of select="name"/></m> is invertible.</xsl:when>
<xsl:otherwise><m><xsl:value-of select="name"/></m> is not invertible.</xsl:otherwise>
</xsl:choose>
</answer>
</exercise>