2x+y=0,求4x²+2xy(x+y)+y³→ 4x²應(yīng)改為4x³,即：4x³+2xy(x+y)+y³
4x³+2xy(x+y)+y³
=4x³+2x²y+2xy²+y³
=2x²(2x+y)+y²(2x+y)
=2x²*0+y²*0
=0
若m²+m-1=0 求m³+2m²+2011
m³+2m²+2011
=m³+m²+m²+2011→(2m²=m²+m²)
=m³+m²-m+m+m²+2011→(需增加：-m+m)
=m(m²+m-1)+m²+m+2012-1→(把2011變?yōu)椋?112-1)
=m*0+(m²+m-1)+2012
=2012
m³+2m²+2011
=m³+2m²+2011→(m²+m-1=0,m²=1-m,m³=m-m²)
=m-m²+2m²+2011
=m²+m+2011
=m²+m-1+2012
=2012
已知（a²+b²-2）（a²+b²）-35=0,a-b=1求a+b ,ab,（b²/a）+（a²/b）
（a²+b²-2）（a²+b²）-35=0
(a²+b²)²-2(a²+b²)-35=0
(a²+b²+5)(a²+b²-7)=0
a²+b²=-5(不合題意,舍去)
a²+b²=7.
a²+b²-2ab=7-2ab,(a-b)²=7-2ab,1=7-2ab,2ab=6,ab=3
a²+b²+2ab=7+2ab,(a+b)²=7+2ab,(a+b)²=7+2*3=13,a+b=±√13.
(b²/a)+(a²/b)=(b³+a³)/ab=(a+b)(a²+b²-ab)/ab=(±√13)(7-3)/3=(±√13)*4/3=(±4√13)/3=