1、1/2x+1/6x+1/12x+1/20x+1/30x+1/42x=1
问题描述：
1、1/2x+1/6x+1/12x+1/20x+1/30x+1/42x=1
2、2+|x+1|+9/3=5
第二题写错了应该是
2|x-1|+9/3=5
答
1.原方程：1.1/(1×2)X+1/(2*3)X+1/(3*4)X+1/(4*5)X+1/(5*6)X+1/(6*7)X=1 然后:(1-1/2)X+(1/2-1/3)X+(1/3-1/4)X+(1/4-1/5)X+(1/5-1/6)X+(1/6-1/7)X=1 后面:X-1/2X+1/2X-1/3X+1/3X-1/4X+1/4X-1/5X+1/5X-1/6X+1/6X-1/7...