1、(a+1)(a-1)(1+a²)2、(-7xy-y)(-7xy+y)3、-(x-1)(x+1)-(3-x)(-3-x)4、2006²-2007×20055、(x^4+y^4)(x^2+y^2)(x+y)(x-y)6、(3a+b-2)(3a-b+2)7、(-4-a)²8、(2x+1)²-4(x+2)(x-2)9、[(-5+x)(-x-5)]10、(3x-a)(3x+a)(9x²-a²)11

Question

1、(a+1)(a-1)(1+a²)
2、(-7xy-y)(-7xy+y)
3、-(x-1)(x+1)-(3-x)(-3-x)
4、2006²-2007×2005
5、(x^4+y^4)(x^2+y^2)(x+y)(x-y)
6、(3a+b-2)(3a-b+2)
7、(-4-a)²
8、(2x+1)²-4(x+2)(x-2)
9、[(-5+x)(-x-5)]
10、(3x-a)(3x+a)(9x²-a²)
11、(3x+4)(3x-4)-(2x+3)(3x-2)
12、(2x-y-3)²
都是计算题

Answer 1

1、(a+1)(a-1)(1+a²)
=(a²-1)(a²+1)
=a^4-1
2、(-7xy-y)(-7xy+y)
=-y(7x-1)(-y)(7x-1)
=y²(49x²-1)
3、-(x-1)(x+1)-(3-x)(-3-x)
=-(x²-1)+(3-x)(3+x)
=-x²+1+9-x²
=10-2x²
4、2006²-2007×2005
=2006²-(2006+1)(2006-1)
=2006²-(2006²-1)
=2006²-2006²+1
=1
5、(x^4+y^4)(x^2+y^2)(x+y)(x-y)
=(x^4+y^4)(x^2+y^2)(x^-y^2)
=(x^4+y^4)(x^4-y^4)
=(x^8-y^8)
6、(3a+b-2)(3a-b+2)
=(3a+b-2)[3a-(b-2)]
=9a²-(b-2)²
=9a²-b²+4b-4
7、(-4-a)²
=(4+a)²
=16+8a+a²
8、(2x+1)²-4(x+2)(x-2)
=4x²+4x+1-4x²+16
=4x+17
9、[(-5+x)(-x-5)]
=-(x+5)(x-5)
=-x²+25
10、(3x-a)(3x+a)(9x²-a²)
=(9x²-a²)(9x²-a²)
=81x^4-18x²a²+a^4
11、(3x+4)(3x-4)-(2x+3)(3x-2)
=9x²-16-(6x²+5x-6)
=9x²-16-6x²-5x+6
=3x²-5x-10
12、(2x-y-3)²
=[2x-(y+3)]²
=4x²-4x(y+3)+(y+3)²
=4x²+y²+9-4xy-12x+6y