Question

1) (2x+5y)(2x-5y)(-4x^2-25y^2) 2) [（x+y)(x-y)-(x-y)^2+2y(x-y)]÷4y 3)

整式乘除 3）（a+b)^2-2a(b+1)-a^2b÷ab 4）（a^2+3)(a-3)-a(a^2-2a-2）

Answer 1

1)
(2x+5y)(2x-5y)(-4x^2-25y^2)
=-(4x^2-25y^2)(4x^2+25y^2)
=-(16x^4-625y^4)
=625y^4-16x^4
2)
[（x+y)(x-y)-(x-y)^2+2y(x-y)]÷4y
=(x-y)(x+y-x+y+2y)÷4y
=4y(x-y)÷4y^
=(x-y)

3）
（a+b)^2-2a(b+1)-a^2b÷ab
=a^2+2ab+b^2-2ab-2a-a
=a^2+b^2-3a

4）
（a^2+3)(a-3)-a(a^2-2a-2)
=a^3-3a^2+3a-9-a^3+2a^2+2a
=5a-a^2-9

Answer 2

1) (2x+5y)(2x-5y)(-4x²-25y²)
=(4x²-25y²)(-4x²-25y²)
=(-25y²)²-(4x²)²
=625y^4-16x^4

2) [（x+y)(x-y)-(x-y)^2+2y(x-y)]÷4y/3)
=(x²-y²-x²+2xy-y²+2xy-2y²)÷(4y/3)
=(-4y²+4xy)÷(4y/3)
=-3y+3x

Answer 3

计算过程如下：
一。(2x+5y)(2x-5y)(-4x^2-25y^2)
=（4x^2-25y^2）(-4x^2-25y^2)
=-(4x^2-25y^2)(4x^2+25y^2)
=-16x^4+625y^4
二。[(x+y)(x-y)-(x-y)^2+2y(x-y)]÷4y
=[(x-y)(x+y-x+y+2y)]÷4y
=4y(x-y)÷4y
=x-y
三。(a+b)^2-2a(b+1)-a^2b÷ab
=a^2+2ab+b^2-2ab-2a-a
=a^2+b^2-3a
四。（a^2+3)(a-3)-a(a^2-2a-2)
=a^3-3a^2+3a-9-a^3+2a^2+2a
=5a-a^2-9

Answer 4

1）原式=（4x²-25y²）(-4x²-25y²)=-16x^4+625y^4.
2）原式=（x-y）(x+y-x+y+2y)÷4y=x-y.