1/(x-6)+1/(x-11)=1/(x-7)+1/(x-12)
(x-11)(x-7)(x-12)+(x-6)(x-7)(x-12)=(x-6)(x-11)(x-12)+(x-6)(x-11)(x-7)
(x-11+x-6)(x-7)(x-12)=(x-6)(x-11)(x-12+x-7)
(2x-17)(x-7)(x-12)=(x-6)(x-11)(2x-19)
(2x-17)(x^2-19x+84)=(2x-17-2)(x^2-17x+66)
(2x-17)(x^2-17x+66-2x+18)=(2x-17-2)(x^2-17x+66)
(2x-17)(x^2-17x+66)-(2x-18)(2x-17)=(2x-17)(x^2-17x+66)-2(x^2-17x+66)
2(x-9)(2x-17)=2(x^2-17x+66)
2x^2-35x+153=x^2-17x+66
x^2-18x+87=0
无实数解.