先化简再求值:(2x+1)(x-1)+x(根号2+1-x),其中x=-根号2

2024-12-27 03:11:42
推荐回答(3个)
回答1:

解:原式=2x²-x-1+(根号2+1)x-x²
=x²+根号2x-1
代入后,得出原式=-1

回答2:

(2x+1)(x-1)+x(根号2+1-x)
=2xx-x-1+根号2*x+x-xx
=xx+根号2*x-1
=2-2-1
=-1

回答3:

:(2x+1)(x-1)+x(根号2+1-x)=2x平方-2x+x-1+x倍根号2+x-x平方=x平方+(2-根号2)x-1=
(-根号2)平方+(2-根号2)(-根号2)-1=2-2倍根号2+2-1=3-2倍根号2