(3a-4b)×(7a-8b)+(11a+2b)×(8b-7a)
=((3a-4b)-(11a+2b))×(7a-8b)
=(3a-4b-11a-2b)×(7a-8b)
=(-6b-8a)×(7a-8b)
=-((8a+6b)×(7a-8b))
=-(56a^2+42ab-64ab-48b^2)
=-(56a^2-22ab-48b^2)
=48b^2+22ab-56a^2
=24b^2+11ab-28a^2
=(3b+4a)(8b-7a)
已知x^4+x^3+x^2+x+1=0,求1+x+x^2+...+x^2004的值.
1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9+x^10+...+x^2004
=(1+x+x^2+x^3+x^4)+x^5(1+x+x^2+x^3+x^4)+x^10+...+x^4)*x^2000
=0