Question

please solve this question guys ​

Answer 1

Answer:

Your answer is here---

Step-by-step explanation:

We know that,  

   $(a-b-c)^{2} = a^{2} +b^{2} +c^{2} -2ab+2bc-2ac$

$(x-2y-z)^{2} \\=(x)^{2} +(2y)^{2} +(z)^{2} -2.x.2y +2.2y.z -2.x.z\\=x^{2} +4y^{2} +z^{2} -4xy +4yz -2xz$