试题详情
阅读下列解答过程,并回答问题.
在(x
2+ax+b)(2x
2﹣3x﹣1)的积中,x
3项的系数为﹣5,x
2项的系数为﹣6,求a,b的值.
解:(x
2+ax+b)•(2x
2﹣3x﹣1)=
2x
4﹣3x
3+2ax
3+3ax
2﹣3bx=①
2x
4﹣(3﹣2a)x
3﹣(3a﹣2b)x
2﹣3bx ②
根据对应项系数相等,有
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmfenced+open%3D%22%7B%22+close%3D%22%22%3E%3Cmtable%3E%3Cmtr%3E%3Cmtd%3E%3Cmn%3E3%3C%2Fmn%3E%3Cmo%3E-%3C%2Fmo%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmi%3Ea%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmo%3E-%3C%2Fmo%3E%3Cmn%3E5%3C%2Fmn%3E%3C%2Fmtd%3E%3C%2Fmtr%3E%3Cmtr%3E%3Cmtd%3E%3Cmn%3E3%3C%2Fmn%3E%3Cmi%3Ea%3C%2Fmi%3E%3Cmo%3E-%3C%2Fmo%3E%3Cmn%3E2%3C%2Fmn%3E%3Cmi%3Eb%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmo%3E-%3C%2Fmo%3E%3Cmn%3E6%3C%2Fmn%3E%3C%2Fmtd%3E%3C%2Fmtr%3E%3C%2Fmtable%3E%3C%2Fmfenced%3E%3C%2Fmath%3E)
解得
![](https://math.21cnjy.com/MathMLToImage?mml=%3Cmath+xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F1998%2FMath%2FMathML%22%3E%3Cmfenced+open%3D%22%7B%22+close%3D%22%22%3E%3Cmtable%3E%3Cmtr%3E%3Cmtd%3E%3Cmi%3Ea%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E4%3C%2Fmn%3E%3C%2Fmtd%3E%3C%2Fmtr%3E%3Cmtr%3E%3Cmtd%3E%3Cmi%3Eb%3C%2Fmi%3E%3Cmo%3E%3D%3C%2Fmo%3E%3Cmn%3E9%3C%2Fmn%3E%3C%2Fmtd%3E%3C%2Fmtr%3E%3C%2Fmtable%3E%3C%2Fmfenced%3E%3C%2Fmath%3E)
回答:
(1)上述解答过程是否正确?
.
(2)若不正确,从第
步开始出现错误,其他步骤是否还有错误?
.
(3)写出正确的解答过程.
知识点
参考答案