x/(2x^2-11x-21)=(x+7)/(x^2-12x+35)x/(2x+3)(x-7)=(x+7)/(x-5)(x-7)x/(2x+3)=(x+7)/(x-5)x(x-5)=(x+7)(2x+3)x^2-5x=2x^2+17x+21x^2+22x+21=0(x+1)(x+21)=0x=-1或x=-21经检验,x=-1和x=-21都是原方程的根....