Question

prove that ( x- y)( x+ y)+( y-z)( y+ z)+( z- x)( z+x)= 0​

Answer 1

Answer:

(x-y)(x+y)+(y-z)+(y+z)+(z-x)(z+x)

=x^2-y^2+y^2-z^2+z^2-x^2

=0

Answer 2

Answer:

x (x+y)-y (x+y)+x (x+y)-y (x+y)+x(x+y)-y(x+y)