下面我都把它们改成正确书写,你看看是不是这样①(a+b)/ab-(b+c)/bc=a/ab+b/ab-b/bc-c/bc=1/b+1/a-1/c-1/b=1/a-1/c②3x/(x-3)²-x/(3-x)=3x/(3-x)²-x/(3-x)=(3x-x(3-x))/(3-x)²=x²/(x-3)²③(3x/(x-2)-x/(x+2))*(x²-4)/x=(3x(x+2)-x(x-2))/(x²-4)*(x²-4)/x=(2x²+8x)/x=2x+4