通分
=[x1(x2-1)-x2(x1-1)]/(x1-1)(x2-1)
=(x1x2-x1-x1x2+x2)/(x1x2-x1-x2+1)
=(x2-x1)/(x1x2-x1-x2+1)
=±√[(x1+x2)²-4x1x2]/[x1x2-(x1+x2)+1]
通分
=[x1(x2-1)-x2(x1-1)]/(x1-1)(x2-1)
=(x1x2-x1-x1x2+x2)/(x1x2-x1-x2+1)
=(x2-x1)/(x1x2-x1-x2+1)
=±√[(x1+x2)²-4x1x2]/[x1x2-(x1+x2)+1]