Question

已知a=-2008,b=2007,c=-2006,求a^2+b^2+c^2+ab+bc-ac的值

Answer 1

“凌君婕”您好,很高兴为您解答!

2(A^2+B^2+C^2+AB+BC-AC)=(A^2+2AB+B^2)+(B^2+2BC+C^2))+(A^2-AC+C^2)

=(A+B)^2+(B+C)^2+(A-C)^2

=1+1+4=6

A^2+B^2+C^2+AB+BC-AC=3

2a^n-50a^n+2

=2a^n(1-25^n)

=2a^n(1-5a)(1+5a)