1.分解因式3x2-12-8a+20x22.化简1/(x2+x)+1/(x2+3x+2)+1/(x2+5x+6)+1/(x2+7x_数学解答

1.分解因式
3x2-12-8a+20x2
2.化简
1/(x2+x)+1/(x2+3x+2)+1/(x2+5x+6)+1/(x2+7x+12)
(a2+3a+3)/(a2+3a+2)-(a2+3a-2)(4-a2)+(1+2a-2a2)/(a2-4-2)

人气：431 ℃　时间：2020-07-09 05:52:50

解答

1、原式=2（3-6-4a+20）=2（17-4a) 2、原式=1/x(x+1) + 1/(x+1)(x+2) + 1/(x+2)(x+3) + 1/(x+3)(x+4)=[(x+2)+x]/x(x+1)(x+2) + [(x+4)+(x+2)]/(x+2)(x+3)(x+4)=(2x+2)/x(x+1)(x+2) + (2x+6)/(x+2)(x+3)(x+4)=2/x(x+2...