①9-x^2+12xy-36y^2
=9-(x^2-12xy+36y^2)
=9-(x-6y)^2
=(3+x-6y)(3-x+6y)
②(a+b)^2-10(a+b)+25 (本题看看是不是题目应该这样?)
=(a+b-5)^2
③100^2-99^2+98^2-97^2+……+2^2-1^2
=(100^2-99^2)+(98^2-97^2)+……+(2^2-1^2)
=2+2+...+2 (共100/2=50个2)
=2x50
=100
④(-2)^101+2^100
=-2^101+2^100
=-2x2^100+2^100
=(-2+1)x2^100
=-2^100
⑤解高次方程
x^3-4x=0
x(x^2-4)=0
x(x+2)(x-2)=0
x=0,or x=-2,or x=2