【導(dǎo)讀】11.下列代數(shù)式中哪些是整式?指出單項式的系數(shù)和次。a,-13x2y,2x-1,x2-xy-y2,1a,1π,7h,xy3+1,2ab+6,25x-by3,-3,0,-π,2.有一組多項式:a+b2,a2-b4,a3+b6,a4-b8,….請觀察它們的構(gòu)成。規(guī)律,用你發(fā)現(xiàn)的規(guī)律寫出第10個多項式:________.3.B由條件可知m+2=6,則m=4.-23x2y,系數(shù)是-23,次數(shù)是3.13.解:因為(a-1)x2ya+1是關(guān)于x,y的五次單項式,當(dāng)a=2時,a2+2a+1=22+2×2+1=4+4+1=9;