因式分解、谁来教教我这些题啊?1、(1+2ab)²-(2+2ab)²2、(7x+y)(7x-y)-(-x+y)(x-y)3、(x-2y-1)(x+2y-1)4、(a-b-2c)²5、(x+2y-3/2)(x-2y+3/2)6、已知,2x-y=1/3,xy=2,求2x^4y³-x³y^4的值.
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因式分解、谁来教教我这些题啊?1、(1+2ab)²-(2+2ab)²2、(7x+y)(7x-y)-(-x+y)(x-y)3、(x-2y-1)(x+2y-1)4、(a-b-2c)²5、(x+2y-3/2)(x-2y+3/2)6、已知,2x-y=1/3,xy=2,求2x^4y³-x³y^4的值.
因式分解、谁来教教我这些题啊?
1、(1+2ab)²-(2+2ab)²
2、(7x+y)(7x-y)-(-x+y)(x-y)
3、(x-2y-1)(x+2y-1)
4、(a-b-2c)²
5、(x+2y-3/2)(x-2y+3/2)
6、已知,2x-y=1/3,xy=2,求2x^4y³-x³y^4的值.
因式分解、谁来教教我这些题啊?1、(1+2ab)²-(2+2ab)²2、(7x+y)(7x-y)-(-x+y)(x-y)3、(x-2y-1)(x+2y-1)4、(a-b-2c)²5、(x+2y-3/2)(x-2y+3/2)6、已知,2x-y=1/3,xy=2,求2x^4y³-x³y^4的值.
1、(1+2ab)²-(2+2ab)²
=(1+2ab+2+2ab)(1+2ab-2-2ab)
=-(4ab+3)
2、(7x+y)(7x-y)-(-x+y)(x-y)
=49x²-y²+x²-2xy+y²
=50x²-2xy
=2x(25x-y)
3、(x-2y-1)(x+2y-1)
=(x-1)²-4y²
=x²-2x+1-4y²
4、(a-b-2c)²
=a²+b²+4c²-2ab-4ac+4bc
5、(x+2y-3/2)(x-2y+3/2)
=[x+(2y-3/2)][x-(2y-3/2)]
=x²-(2y-3/2)²
=x²-4y²+6y-9/4
6、2x-y=1/3,xy=2,
2x^4y³-x³y^4
=x³y³(2x-y)
=2³*(1/3)
=8/3