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一元二次方程ax^2+bx+c=0中,abc都是实数,且(2-a)^2+√下(a^2+b+c)+|c+8|=0,求代数式

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/13 03:10:29
一元二次方程ax^2+bx+c=0中,abc都是实数,且(2-a)^2+√下(a^2+b+c)+|c+8|=0,求代数式x^2+x+1的值
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平方和绝对值和根号都是大于或等于0的 所以只能都等于0才能相加为0
2-a=0得 a=2 c+8=0 得c=-8
a²+b+c=0 得b=4
2x²+4x-8=0 得x²+2x-4=0
(x+1)²=5 x=±√5-1
x²+x+1=4-2x+x+1=5-x=6±√5