Question

Factorise the following:

Answer 1

Step-by-step explanation:

${x}^{2} + {y}^{2 } + {z}^{2} -2 (xy + yz + xz)\\={(x + y + z)}^{2}\\\\2{x}^{2}+{y}^{2}+8 {z}^{2}-2 \sqrt{2} xy+4\sqrt{2}yz + 8xz \\ = {( \sqrt{2}x - y - 2 \sqrt{2}z ) }^{2}$