用因式分解法解下列方程1.4x^2-x-5=02.(x^2-x)(x^2-x-3)+3(x^2-x)=4

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用因式分解法解下列方程1.4x^2-x-5=02.(x^2-x)(x^2-x-3)+3(x^2-x)=4
用因式分解法解下列方程
1.4x^2-x-5=0
2.(x^2-x)(x^2-x-3)+3(x^2-x)=4

用因式分解法解下列方程1.4x^2-x-5=02.(x^2-x)(x^2-x-3)+3(x^2-x)=4
1.4x^2-x-5=0
4x²+4x-5x-5=0
4x(x+1)-5(x+1)=0
(4x-5)(x+1)=0
x=5/4
x=-1
2.(x^2-x)(x^2-x-3)+3(x^2-x)=4
(x^2-x)^2-3(x^2-x)+3(x^2-x)=4
(x^2-x)^2=4
x^2-x=2,x^2-x=-2
若x^2-x=2,x^2-x-2=0,(x-2)(x+1)=0,x=2,x=-1
若x^2-x=2,x^2-x+2=0,判别式小于0,无解
所以x=2,x=-1

1.4x^2-x-5=0
==>(4x-1)(x+1)=0
==>x=1/4或x=-1
2.(x^2-x)(x^2-x-3)+3(x^2-x)=4
==>(x^2-x)(x^2-x-3+3)=4
==>(x^2-x)(x^2-x)=4
==>(x^2-x)=±2
当(x^2-x)=2时
==>x^2-x-2=0
==>(x-2)(x+1)=0
==>x=2或x=-1
当(x^2-x)=-2时
==>x^2-x+2=0
==>(x+2)(x-1)=0
==>x=-2或x=1