=\frac{\sqrt{37}-6-(\sqrt{37}+6)}{(\sqrt{37}-6)(\sqrt{37}+6)}=\frac{-12}{\sqrt{37}^{2}-6^{2}}=\frac{-12}{37-36}=\frac{-12}{1}= -12
=\frac{\sqrt{37}-6-(\sqrt{37}+6)}{(\sqrt{37}-6)(\sqrt{37}+6)}=\frac{-12}{\sqrt{37}^{2}-6^{2}}=\frac{-12}{37-36}=\frac{-12}{1}= -12