f(x)g(x)的首项系数 f(x)的首项系数×8()的首项系数 3)运算律 f(o)+g(x)=g(x)+f(x) (f(x)+g(x)+H(x)=f(x)+(8(x)+h(x) f(g(x=g(x)f(x C(g(oh(x)=f(o(g(h(o) f(x)(g(x)+H(x)=f(x)g(x)+f(x)h(x) f(x)g(x)=f(x)h(x),f(x)≠0→g(x)=h(xf x g x ( ) ( ) 的首项系数 = f x( ) 的首项系数× g x( ) 的首项系数. 3) 运算律 f x g x g x f x ( ) ( ) ( ) ( ) + = + ( ( ) ( )) ( ) ( ) ( ( ) ( )) f x g x h x f x g x h x + + = + + f x g x g x f x ( ) ( ) ( ) ( ) = ( ( ) ( )) ( ) ( )( ( ) ( )) f x g x h x f x g x h x = f x g x h x f x g x f x h x ( )( ( ) ( )) ( ) ( ) ( ) ( ) + = + f x g x f x h x f x g x h x ( ) ( ) ( ) ( ), ( ) 0 ( ) ( ) =   =