Question

已知多项式2x+3xy-2y-x+8y-6可因式分解为(x+2y+m)(2x-y+n)的形式.求(m+1)/(n-1)的

Answer 1

因为2x2+3xy-2y2-x+8y-6=(x+2y+m)(2x-y+n)=2x^2+3xy-2y^2+(n+2m)x+(2n-m)y+mn,所以n+2m=-1,2n-m=8,mn=-6,解方程组得m=-2,n=3,所以(m^3+1)/(n^2-1)=-7/8.

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