Question

计算下列题，急啊！

(-x^3)^2(-x^2)^3+(-x^3)^4.2a(a-3)^2-6a^2(3-a)-8a(a-3).若3x^m+2ny^8与-2x^2y^3m+4n是同类项，求m-n的值.(四分之三a^2b-五分之三ab^2)(-三分之一ab)^2+十二分之一a^4b^3. (-2x-3y)^2-(x-2y+3)(x-2y-3)-9. 3(x^2-xy)+[xy-(3x^2-xy-1)]-x^2,x=0.2,y=1

Answer 1

1、a^2-b^2=（a+b）（a-b）=5×2=10
2、
x-y=(x-z)-(y-z)=2
x-z=2+(y-z)=2+2=4
x+y=(x+z)+(y-z)=14
x+z=14-(y-z)=14-2=12
x^2-z^2
=(x+z)(x-z)
=12×4
=48
3、
n+1998]^2-10^2=[n+1998+10][n+1998-10]=[n+2008][n+1988][n+1998]的平方=65432178
[n+2008][n+1988]=[n+1998]的平方-100=65432078

4、

(2a+2b+1)(2a+2b-1)=63
(2a+2b)²-1²=63
(2a+2b)²=64
2a+2b=8 或者 2a+2b=-8
a+b=4 或者 a+b=-4