Question

Tính:              a/ (x - y ) + (y - z ) - (x - z )             

                      b/ (x² + y² - z² ) + ( y² + z² - x² ) - ( y² - x² - z² )

Answer 1

a/(x-y)+(y-z)-(x-z)

=x-y+y-z-x+z=0

b/(x²+y²-z²)+(y²+z²-x²)-(y²-x²-z²)

=x²+y²-z²+y²+z²-x²-y²+x²+z²

=x²+y²+z²

Answer 2

a/(x-y)+(y-z)-(x-z)

=x-y+y-z-x+z=0

b/(x²+y²-z²)+(y²+z²-x²)-(y²-x²-z²)

=x²+y²-z²+y²+z²-x²-y²+x²+z²

=x²+y²+z²