Question

 (x – y)(x + y) + (y – z)(y + z) + (z – x) (z + x) is equal to​

Answer 1

Step-by-step explanation:

sol: (x-y)(x+y) + (y-z)(y+z) + (z-x)(z+x)

(x^2 - y^2) + (y^2 - z^2) + (z^2 - x^2)

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

=1