(7a + 7b) / (5c)^2 (14c / 6b + 6a)
= (7a + 7b) / 25c^2 (14c / 6b + 6a)
= (7a + 7b) / 25c^2 (14c / 6b) + (7a + 7b) / 25c^2 6a
= 98ac / 150bc^2 + 42a / 25c^2 + 98bc / 150bc^2 + 42b / 25c^2
= (98ac + 98bc) / 150bc^2 + (42a + 42b) / 25c^2
= 98(a + b) / 150bc + 42(a + b) / 25c^2
= (98(a + b) / 150bc + 42(a + b) / 25c^2
= 98(a + b) / 150bc + 252(a + b) / 375c^2
= 2(a + b) / 3bc + 2(a + b) / 5c^2
= 2(a + b)(5c + 3b) / 15bc^2