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若a^2-a=1,求a^3+a^2-3a+8的值
人气:440 ℃ 时间:2020-05-28 16:46:40
解答
解析
a²-a=1
a³+a²-3a+8
=a(a²+a-3)+8
=a(a²-a+2a-3)+8
=a(2a-3+1)+8
=a(2a-2)+8
=2a²-2a+8
=2(a²-a)+8
=2+8
=10
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