Question

一道很难的数学题小明在求代数式2x²-3x²y+nx²y-3x²的值时,发现所求

Answer 1

2x²-3x²y+nx²y-3x²

=-x^2-(3x^2-nx^2)y

代数式的值与y无关

即3x^2-nx^2=0

n=3

x=-2,y=2004时

原式

=-x^2

=-(-2)^2

=-4