Question

12．试说明多项式$\frac{1}{2}$x³-$\frac{1}{4}$x+0.2x²+0.25x-0.5x³-$\frac{1}{5}$x²的值与x无关．

Answer 1

分析 先合并同类项，计算得到该式=0，则说明多项式$\frac{1}{2}$x³-$\frac{1}{4}$x+0.2x²+0.25x-0.5x³-$\frac{1}{5}$x²的值与x无关．

解答 解：$\frac{1}{2}$x³-$\frac{1}{4}$x+0.2x²+0.25x-0.5x³-$\frac{1}{5}$x²，
=0.5x³-0.25x+0.2x²+0.25x-0.5x³-0.2x²，
=（0.5-0.5）x³-（0.25-0.25）x+（0.2-0.2）x²，
=0，
即多项式$\frac{1}{2}$x³-$\frac{1}{4}$x+0.2x²+0.25x-0.5x³-$\frac{1}{5}$x²的值与x无关．

点评 本题考查了多项式．解题是实质是合并同类项．