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2. Given $a^{2}+2 a=1$, then the value of the polynomial $2 a^{5}+7 a^{4}+5 a^{3}+2 a^{2}+5 a+1$ is

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匹答案 $\rrbracket 4$

Match the answer $\rrbracket 4$

Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic, difficulty and ordering added by this site.