M
minhduccay


Cho m + n + p = 0. Chứng minh:
$(\frac{m-n}{p} + \frac{n-p}{m} + \frac{p-m}{n})(\frac{p}{m-n} + \frac{m}{n-p} + \frac{n}{p-m})$=9
$(\frac{m-n}{p} + \frac{n-p}{m} + \frac{p-m}{n})(\frac{p}{m-n} + \frac{m}{n-p} + \frac{n}{p-m})$=9