ANSWER
C and D
EXPLANATION
Step 1: Given that:
[tex]C\text{ = }\begin{bmatrix}{2} & 1{} & {} \\ {1} & {}2 & {} \\ {2} & {1} & \end{bmatrix}\text{ and D = }\begin{bmatrix}{\sqrt[]{4}} & 1{} & {} \\ {1} & {}\sqrt[]{4} & {} \\ {\sqrt[]{4}} & {1} & \end{bmatrix}[/tex]
Step 2: Simplify matrix D
[tex]\begin{gathered} \text{D = }\begin{bmatrix}{\sqrt[]{4}} & 1{} & {} \\ {1} & {}\sqrt[]{4} & {} \\ {\sqrt[]{4}} & {1} & \end{bmatrix}\text{ = }\begin{bmatrix}{2} & 1{} & {} \\ {1} & {}2 & {} \\ {2} & {1} & \end{bmatrix}\text{ since }\sqrt[]{4}\text{ = 2.} \\ \end{gathered}[/tex]
Hence, matrices C and D are equal.
