Using appropriate prperties find:
4/5*(-2/3)- 4/5* 1/2 + 1/7* 2/3
4/5*(-2/3) = -8/15
4/5* 1/2 = 4/10 = 2/5
1/7* 2/3 = 2/21
LCD = 3*5*7 = 105
-8/15 - 2/5 + 2/21 = -56/105 - 42/105 + 10/105 = -88/105
4/5*(-2/3)- 4/5* 1/2 + 1/7* 2/3
4/5* 1/2 = 4/10 = 2/5
1/7* 2/3 = 2/21
LCD = 3*5*7 = 105
-8/15 - 2/5 + 2/21 = -56/105 - 42/105 + 10/105 = -88/105