2015杭州摸拟.已知代数式nx平方-1的差乘以xm次方 3nx 2化简后是一个四次多项式，并且不

(nx²-1)(x^m+3nx+2) =nx^(2+m)-x^m+3n²x³-3nx+2nx²-2 ∴ 2+m=4 m=2 原式= =nx^4+3n²x³-x²+2nx²-3nx-2 =nx^4+3n²x³+(2n-1)x²-3nx-2 ∴ 2n-1=0 n=1/2 一次项系数=-3n=-3/2