几道初一数学题(快 简单的）

-3XY^2(X^2Y+5XY^2)
(M^2N-MN^2)(-M^2N-MN^2)
(2X-Y)(-2X+Y)
-(X-Y)(3X-2Y)
(2X-Y+Z)(2X+Y-Z)
(A-B-C)^2
-X^3-4X^2-4X
4A^2+12AB+9B^2
X^4-8X^2+16
注意看平方

-3XY^2(X^2Y+5XY^2)
=-3X^3Y^3-15X^2Y^4

(M^2N-MN^2)(-M^2N-MN^2)
=M^2N^4-M^4N^2

(2X-Y)(-2X+Y)
=-（2X-Y）^2
=-4X^2+4XY-Y^2

-(X-Y)(3X-2Y)
=-(3X^2-5XY+2Y^2)
=-3X^2+5XY-2Y^2

(2X-Y+Z)(2X+Y-Z)
=4X^2-(Y-Z)^2
=4X^2-Y^2+2YZ-Z^2

(A-B-C)^2
=A^2+B^2+C^2-2AB-2BC-2AC

-X^3-4X^2-4X
=-X(X^2+4X+4 )
=-X(X+2)^2

4A^2+12AB+9B^2
=(2A+3B)^2

X^4-8X^2+16
=(X^2-4)^2
=(X+2)^2(X-2)^2

3XY^2(X^2Y+5XY^2)
=3x^2y^3(x+5y)
(M^2N-MN^2)(-M^2N-MN^2)

=-m^2n^2(m^2-n^2)
= -m^2n^2(m+n)(m-n)
(2X-Y)(-2X+Y)
=-(2x-y)^2
-(X-Y)(3X-2Y)
=-(3x^2-2xy-3xy+2y^2)
=-3x^2+5xy-2y^2
(2X-Y+Z)(2X+Y-Z)
=[4x^2-(y-z)^2]
=4x^2+y^2+2yz-z^2
(A-B-C)^2
=A^2+B^2+c^2-2AB-2AC+2BC
-X^3-4X^2-4X
=-x(x^2+4x+4)
=-x(x+2)^2
4A^2+12AB+9B^2
=(2A+3B)^2

X^4-8X^2+16
=(x^2-4)^2