想知道x+2怎么变x-2 提出个负号?x-2又怎么变2-x?

x+2怎么变都变不成x-2
x-2=-(-x+2)=-(2-x)
即x-2提取负号变2-x有道题,(x+2/x-2+2-x/x+2) ÷x/x-2(x+2/x-2+2-x/x+2) ÷x/x-2=[(x+2(/(x-2) - (x-2)/(x+2)] ÷ x/x-2={[(x+2)²-(x-2)²]/(x+2)(x-2)}÷[ x/(x-2)]=[8x/(x+2)(x-2)]*[(x-2)/x]=8/(x+2)[(x+2)²-(x-2)²]这哪来的平方.[(x+2(/(x-2) - (x-2)/(x+2)]={[(x+2)²-(x-2)²]/(x+2)(x-2)}通分来的我再问最后一个, x²-2x-2=0的两个根, 正数根是哪个..x²-2x-2=0x²-2x+1=3(x-1)²=3x-1=√3或x-1=-√3x=√3+1或x=-√3+1前者是正根