因式分解1.已知:x+y=1,x
1。x(x+y)(x-y)-x(x+y)^2
=x(x+y)[(x-y)-(x+y)]
=-2xy(x+y)
=-2*(-1/2)*1
=1
2。 a^2-2ab+b^2-10a+10b+25
=(a-b)^2-10(a-b)+25
=(a-b-5)^2
=(96-92-5)^2
=(-1)^2=1
3。 x^4-46x^2+25
=x^4-10x^2+25-36x^2
=(x^2-5)^2-(6x)^2
=(x^-5+6x)(x^2-5-6x)
=(x^2+6x-5)(x^2-6x-5)
4。 a^2-b^2-c^2-2bc
=a^2-(b+c)^2
=(a+b+c)(a-b-c...全部
1。x(x+y)(x-y)-x(x+y)^2
=x(x+y)[(x-y)-(x+y)]
=-2xy(x+y)
=-2*(-1/2)*1
=1
2。 a^2-2ab+b^2-10a+10b+25
=(a-b)^2-10(a-b)+25
=(a-b-5)^2
=(96-92-5)^2
=(-1)^2=1
3。
x^4-46x^2+25
=x^4-10x^2+25-36x^2
=(x^2-5)^2-(6x)^2
=(x^-5+6x)(x^2-5-6x)
=(x^2+6x-5)(x^2-6x-5)
4。
a^2-b^2-c^2-2bc
=a^2-(b+c)^2
=(a+b+c)(a-b-c)<0
。收起