(1)2X+3)/(X-1)(X+2)=A/x-4+B/x+2,那A-B= (2)3X2-X=1,则6X3+7X2-5X+2008=

题目

(1)2X+3)/(X-1)(X+2)=A/x-4+B/x+2,那A-B= (2)3X2-X=1,则6X3+7X2-5X+2008=

答案

(1)（2X+3)/(X-1)(X+2)=(2X-2+5)/(X-1)(X+2)=5/3(X-1)+1/3(x+2)由A/x-1=5/3(X-1) B/x+2= 1/3(x+2)A=5/3 B=1/3 A-B=4/3(2)6X3+7X2-5X+2008=6X3-2X2+9X2-5X+2008=2X(3X2-X)+9X2-5X+2008=2X+9X2-5X+2008=3(3X2-X)+2008=...