(x-2)(xx+mx+n)=xxx+3xx-7x-6(x-2)(xx+mx+n) 展开=x³+mx²+nx-2x²-2mx-2n=x³+(m-2)x²+(n-2m)x-2n因为有x³+(m-2)x²+(n-2m)x-2n=x³+3x²-7x-6所以m-2=3 m=5-2n=-6 n=3...