x+2+4/x-2; (a-1/1-a)÷(a^2-a+1/a^2-2a+z); ( m +mn/m-n)÷(m-mn/m+n); (a/a+1+ 1)÷(1- 3a^2/1-a^2)

问题描述:

x+2+4/x-2; (a-1/1-a)÷(a^2-a+1/a^2-2a+z); ( m +mn/m-n)÷(m-mn/m+n); (a/a+1+ 1)÷(1- 3a^2/1-a^2)

x+2+4/x-2; =(x²-4+4)/(x-2)=x²/(x-2)(a-1/1-a)÷(a^2-a+1/a^2-2a+1);=(a-a²-1)/(1-a)÷(a²-a+1)/(a-1)²=(a²-a+1)/(a-1)÷(a²-a+1)/(a-1)²=a-1 ( m+mn/m-n)...