4/(x-5)-(x-5)/(x-12)=(x-33)/(x-5)(x-12)两边乘(x-5)(x-12)4(x-12)-(x-5)^2=x-33x^2-10x+25-4x+48+x-33=0x^2-13x+40=0(x-5)(x-8)=0x=5,x=8分式方程要检验经检验,x=5使分母为0,舍去所以x=8