简便计算和解方程各一题1/6+1/12+1/20+1/30 3（X+2）=4X+1

Question

简便计算和解方程各一题
1/6+1/12+1/20+1/30 3（X+2）=4X+1

Answer 1

1/6+1/12+1/20+1/30
=1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6
=1/2-1/6
=1/3
3（X+2）=4X+1
3X+6=4X+1
4X-3X=6-1
X=5