Question

1 x^2+5x-990=0，则x^3+6x^2-985x+1017=__ 2 1+X+x^2=0则x^2010+x^2009+x^2008+..+x+1=___

3. 已知m,n都是自然数，且m^2-n^2=12,m,n值是___
4.已知abc都是正整数，且a＞b a^2+bc-ab-ac=7则a-c=___
急急急急急

Answer 1

1.x^3+6x^2-985x+1017
=x^3+5x^2-990x+x^2+5x-990+2007
=x(x^2+5x-990)+x^2+5x-990+2007
=(x+1)(x^2+5x-990)+2007
=2007
2.x^2010+x^2009+x^2008+..+x+1
=x^2008(x^2+x+1)+x^2005(x^2+x+1)+......+x^4(x^2+x+1)+x(x^2+x+1)+1
=1
3.m=4,n=2
4.a^2+bc-ab-ac=7
a^2-ab+bc-ac=7
a(a-b)-c(a-b)=7
(a-b)(a-c)=7
∵a＞b∴a-b＞0
a-c=1或7