(a+b+c)^2(a-b-c)^2(a+c-b)^2(-a-b-c)^2答案：(a+b+c)^2=a^2+b^2+c^2+2ab+2bc+2ac(-a-b-c)^2=a^2+b^2+c^2+2ab+2bc+2ac(a+c-b)^2=a^2+b^2+c^2-2ab-2bc+2ac(a-b-c)^2=a^2+b^2+c^2-2ab+2bc-2ac