方程两边同乘（x-2）x
得1200x-1200(x-2)=30*(x-2)x
1200x-1200x+2400=30x²-60x
30x²-60x-2400=0
x²-2x-80=0
(x-10)(x+8)=0
x=10或x=-8
解方程：(1200/x-2)-(1200/x)=30
方程两边同乘（x-2）x
得1200x-1200(x-2)=30*(x-2)x
1200x-1200x+2400=30x²-60x
30x²-60x-2400=0
x²-2x-80=0
(x-10)(x+8)=0
x=10或x=-8