question_answer

If \[x\,=\,y\,=\,z,\] then find the value of \[{{x}^{2}}\,+\,{{y}^{2}}\,+\,{{z}^{2}}\,+\,2xy.\]

A)  \[5{{x}^{2}}\]                                   

B)  \[5{{y}^{2}}\]

C)  \[5{{z}^{2}}\]                        

D)  All of these

E)  None of these