不难的题目,不难的题目......

1、(a^2+4)^2-16a^2
=a^4+8a^2+16-16a^2=a^4-8a^2+16=(a^2-4)^2
2、((2a-1)^2-(a+2)^2)÷(a-3)
=[(2a-1+a+2)(2a-1-a-2)]÷(a-3)=(3a+1)(a-3)÷(a-3)
=3a+1
3、(a+2)^2-2a(a+2)
=a^2+2a+4-4a-4=a^2-2a=a(a-2)
4、-5a^3+10a^2-5a
=-5a(a^2-2a+1)=-5a(a-1)^2
5、m^4-2m^2+1
=(m^2-1)^2
6、(x+y)^2-8(x+y-2)
=(x+y)^2-8(x+y)+16=(x+y-4)^2
7、解方程:(3x-1)^2=(2-5x)^2
(3x-1)^2-(2-5x)^2=0
(3x-1+2-5x)(3x-1-2+5x)=(1-2x)(8x-3)=0
x=1/2或3/8
8、化简,求值:((a^2+b^2)^2-4a^2b^2))÷(a^2-b^2),a=2,b=1/3
((a^2+b^2)^2-4a^2b^2))÷(a^2-b^2)
=(a^2+b^2+2ab)(a^2+b^2-2ab)÷(a+b)(a-b)
=(a+b)^2(a-b)^2÷(a+b)(a-b)
=(a+b)(a-b)自己算吧！
9、求满足等式a^2=b^2+23的整数a,b的值
a^2-b^2=23
(a+b)(a-b)=23 因为a,b是整数，所以a-b=1,a+b=23 解得a=12,b=1
10、若a^2+2a-2=0求a^3+4a^2+2a+6的值
a^2+2a-2=0所以（a+1）^2=3
a^3+4a^2+2a+6=a(a^2+2a+1)+2a^2+a+6=3a+2a^2+a+6
=2a^2+4a+6=2(a^2+2a+1)+4=6+4=10

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