Question

36、多項(xiàng)式x^m+（m+n）x²-3x+5是關(guān)于x的三次四項(xiàng)式，且二次項(xiàng)系數(shù)是-2，則m=

3

，n=

-5

．

Answer 1

分析：根據(jù)多項(xiàng)式的項(xiàng)、項(xiàng)的次數(shù)和系數(shù)的定義解答．多項(xiàng)式的次數(shù)是多項(xiàng)式中最高次項(xiàng)的次數(shù)，多項(xiàng)式的項(xiàng)數(shù)為組成多項(xiàng)式的單項(xiàng)式的個(gè)數(shù)．

解答：解：由于多項(xiàng)式中最高次項(xiàng)xm的次數(shù)是3次，故m=3；
又由于二次項(xiàng)（m+n）x²的系數(shù)m+n的值是-2，則3+n=-2，解得n=-5．
則m=3，n=-5．

點(diǎn)評(píng)：本題考查了同學(xué)們對(duì)多項(xiàng)式的項(xiàng)、項(xiàng)的系數(shù)和次數(shù)定義的掌握情況．