Prove the following identities- 1+a1111+a1111+a=a3+3a2

Prove the following identities- $|\begin{matrix} 1 + a & 1 & 1 \\ 1 & 1 + a & 1 \\ 1 & 1 & 1 + a \end{matrix}| = a^{3} + 3 a^{2}$

Matching exercise

Match the items on the right to the items on the left.

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