Question

已知a分之1+b分之1+c分之1=-2,求分式ab分之a+b+bc分之b+c+ac分之c+a的值，详细过程！

还有一题！ x+2分之1，x²-4分之4x，2-x分之2，通分！ 没学1

Answer 1

a+b/ab + b+c/bc + c+a/ac
=1/b + 1/a + 1/c + 1/b + 1/a + 1/c
=2(1/a + 1/b + 1/c)
∵1/a + 1/b + 1/c=-2
∴所求=2×(-2)=-4

追问

看补充的问题！

追答

1/x+2 + 4x/x²-4 + 2/2-x
=x-2/(x+2)(x-2) + 4x/(x+2)(x-2) -2(x+2)/(x+2)(x-2)
=x-2+4x-2x-4/(x+2)(x-2)
=3(x-2)/(x+2)(x-2)
=3/x+2