Question

如果可以,两道题都麻烦讲给我听一下

Answer 1

由已知：a+b=-c,b+c=-a,a+c=-b,

原式=a/b+a/c+b/c+b/a+c/a+c/b

=(a+c)/b+(a+b)/c+(b+c)/a

=-b/b-c/c-a/a

=-3.

a^3+b^3

=(a+b)(a²-ab+b²)

=(a+b)[(a+b)²-3ab]

∵a+b=1,

∴a^3+b^3=1-3ab

∴a^3+b^3+3ab=1.