已知x²+x-1=0,则x³+2x²+3=急啊!
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/29 22:39:36
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已知x²+x-1=0,则x³+2x²+3=急啊!
已知x²+x-1=0,则x³+2x²+3=
急啊!
已知x²+x-1=0,则x³+2x²+3=急啊!
解
x²+x-1=0
x²+x=1
x³+2x²+3
=x(x²+x)+x²+3
=x+x²+3
=1+3
=4