Answer:
Hi there!
The correct answer is: [tex]2x^{2} + y^{2} + z^{2} - 2\sqrt{2} xy - 2\sqrt{2} xz + 2yz[/tex]
Step-by-step explanation:
First of all I want to clarify I used to the fourth identity to solve this problem.
The fourth identity is: [tex](x+y+z)^{2} = x^{2} + y^{2} + z^{2} + 2xy + 2xz + 2yz[/tex]
