Verified answer

б) 1/2а + 1/3а - 1/6а = 3/6а + 2/6а - 1/6а = 5/6a - 1/6a = 4/6а = 2/3а

в) 0,9b - 1,3b + 0,7b = 0,9b + 0,7b - 1,3b = 1,6b - 1,3b = 0,3b

г) х - 0,2х - 0,7х = х - (0,2х + 0,7х) = х - 0,9х = 0,1х

д) 1/12m - 1/4m - 1/3m = 1/12m - 3/12m - 4/12m = 1/12m - (3/12m + 4/12m) = 1/12m - 7/12m = - 6/12m