一道分式的乘除法求当x=-4时,式子（4-4x+x^2）分之（2x^2-18）÷[(x+3)·(x^2+x-6)分之(3

原式=[2(x+3)(x-3)/(x-2)²]÷[-(x-3)(x+3)/(x+3)(x-2)]=-[2(x+3)(x-3)/(x-2)²]×[(x-2)/(x-3)]=-[2(x+3)(x-3)(x-2)/[(x-2)²(x-3)]=-2(x+3)/(x-2)=-2*(-1)/(-6)=-1/3