Question

把多項(xiàng)式3x⁴y-xy⁴-5x²y³+x³y²+7按x的降冪排列為

3x⁴y+x³y²-5x²y³-xy⁴+7

；該多項(xiàng)式是幾次幾項(xiàng)式

五次五項(xiàng)式

．

Answer 1

分析：先根據(jù)降冪排列的方法得到3x⁴y+x³y²-5x²y³-xy⁴+7，然后根據(jù)多項(xiàng)式的有關(guān)概念可確定該多項(xiàng)式是五次五項(xiàng)式．

解答：解：多項(xiàng)式3x⁴y-xy⁴-5x²y³+x³y²+7按x的降冪排列為3x⁴y+x³y²-5x²y³-xy⁴+7；該多項(xiàng)式是五次五項(xiàng)式．
故答案為3x⁴y+x³y²-5x²y³-xy⁴+7；

點(diǎn)評：本題考查了多項(xiàng)式：幾個單項(xiàng)式的和叫做多項(xiàng)式，每個單項(xiàng)式叫做多項(xiàng)式的項(xiàng)，其中不含字母的項(xiàng)叫做常數(shù)項(xiàng)．多項(xiàng)式中次數(shù)最高的項(xiàng)的次數(shù)叫做多項(xiàng)式的次數(shù)．