[(X-1)-8/(X+1)]除以(X+3)/(X+1)=(x²-1-8)/(x+1)×(x+1)/(x+3)=(x²-9)/(x+3)=(x+3)(x-3)/(x+3)=x-3代入x=3-√2原式=3-√2-3=-√2希望能帮到你O(∩_∩)O
拜托说清楚点好吗，有歧义的！
