因式分解:1、4a³-a;2、6xy²-9x²y-y³;3、解方程:x-2分之1
1个回答

1、4a³-a

=a(4a²-1)

=a(2a+1)(2a-1)

2、6xy²-9x²y-y³

=-y(9x²-6xy+y²)

=-y(3x-y)²

3、解方程:

x-2分之1-x=2-x分之1-(2)

(1-x)/(x-2)=-1/(x-2) -2

乘以x-2得

1-x=-1-2(x-2)

1-x=-1-2x+4

-x+2x=3-1

x=2

经检验,x=2时,分母x-2=0,为增根

所以原方程无解

4、计算:

(x-y)²-(x+y)(x-y)

=x²-2xy+y²-(x²-y²)

=x²-2xy+y²-x²+y²

=2y²-2xy

=2y(y-x)

怎么老是显示不正常啊