1.hasil 2/5-1/3-6/7 2.1x+1=14x-1 3.6x+2=14 4.

1)

2/5 - 1/3 -6/7 = (42-35-90)/105 = -83/105

2) 1x + 1 = 14x - 1
14x - 1x = 1 + 1
13x = 2
x = 2/13

3) 6x + 2 = 14
6x = 14-2 = 12
x = 12/6
x = 2