Answer:
x² + z² + 2xz - y²
Explanation:
(x - y + z) (x + y + z)
Rearranging to make it an identity,
=> (x + z + y) (x + z - y)
=> ((x + z) + y) ((x-z) - y)
We know the identity,
(a + b)(a-b) = a² - b²
=> (x + z)² - y²
We know the identity,
(a + b)² = a² + b² + 2ab
Expanding,
=> x² + z² + 2xz - y²