[tex] \frac{ m^{2} -8n}{(m-2)(n-5)}- \frac{2m-8n}{(2-m)(5-n)} = \frac{ m^{2} -8n}{(m-2)(n-5)}- \frac{2m-8n}{(m-2)(n-5)}=[/tex][tex]= \frac{ (m^{2} -8n)-(2m-8n)}{(m-2)(n-5)}= \frac{ (m^{2} -8n)-(2m-8n)}{(m-2)(n-5)}=\frac{ m^{2} -2m}{(m-2)(n-5)}=\frac{ m(m-2)}{(m-2)(n-5)}=[/tex]