Question

解方程1/x+3-1/x+7=1/x+2-1/x+6

Answer 1

是1/（x+3）-1/（x+7）=1/（x+2）-1/（x+6）这样的吧,两边都通分得4/[(x+3)(x+7)]=4/[(x+2)(x+6)],所以[(x+3)(x+7)=(x+2)(x+6）,两边展开得x^2+10x+21=x^2+8x+12;消去x^2；并移项得2x=-9；所以x=-4.5;