Answer:
Sure, here are the answers:
2/7 + 5/3 - 4/5 - 1/3 = (2/7 + 5/3) - (4/5 + 1/3)
= (6/21 + 15/21) - (9/15 + 7/15)
= 21/21 - 16/15 = 5/15 = 1/3
3/7 - 4/7 - 11/9 + 7/9 + 9/7 + 7/7 = (3/7 - 4/7) + (-11/9 + 7/9) + (9/7 + 7/7)
= (-1/7) + (-4/9) + (16/7) = -1/7 - 4/9 + 16/7 = 16/7 - 1/7 - 4/9 = 15/7 - 4/9 = (45/63) - (28/63) = 17/63
2/5 + 8/3 - 11/4 - 2/5 + 15/5 + 3/15 = (2/5 + 8/3) - (11/4 + 2/5) + (15/5 + 3/15)
= (6/15 + 40/15) - (27/20 + 4/5) + (3/1 + 1/5)
= 46/15 - 31/20 + 8/5 = (230/60) - (31/20) + (40/20) = (230 - 31 + 40)/60 = 179/60 = 13/20
-8/9 - 13/7 + 17/9 + 7/7 + 21/7 = (-8/9 - 13/7) + (17/9 + 7/7) + 21/7
= (-59/63 + 126/63) + (147/63) = 67/63 + 147/63 = 214/63 = 22/9
Explanation: