1、y3-2y2=5y-10
y3-2y2-5y+10=0
y2(y-2)-5(y-2)=0
(y-2)(y2-5)=0
y=2或y=±√5
2、a/(x+2)+b/(x-2)=4x/(x2-4)
(ax-2a+bx+2b)/(x2-4)=4x/(x2-4)
(a+b)x-2a+2b=4x
得出a+b=4、-2a+2b=0
推出a=b=2
3、[2x*x*(x+1)-(m+1)(x-1)]/[x(x-1)(x+1)]=[(x+1)(x-1)(x+1)]/ [x(x-1)(x+1)]
2x3+2x2-(m+1)x+(m+1)=x3+x2-x-1
x3+x2-mx+(m+2)=0
有增根,说明,x=0,x=1或者x=-1
当x=0时,m+2=0,m=-2
当x=1时,1+1-m+m+2=0,不成立
当x=-1时,-1+1+m+m+2=0,m=-1
综上所述,m=-2或m=-1