Given a / b = C / D = E / F = 2 / 7, find the value of (a-2c + 3e) / (2b-4d + 6F)

Given a / b = C / D = E / F = 2 / 7, find the value of (a-2c + 3e) / (2b-4d + 6F)

because
a/b=c/d=e/f=2/7
therefore
7a=2b
7c=2d
7e=2f
(a-2c + 3e) / (2b-4d + 6F)
=1 / 2 × (a-2c + 3e) / (b-2d + 3f)
=(a-2c + 3e) / [7 / 2 (a-2c + 3e)]
=1/2×2/7
=1/7

If a, C, D are integers and B is a positive integer, and a + B = C, B + C = D, C + D = a is satisfied, then the maximum value of a + B + C + D is ()
A. -1B. -5C. 0D. 1

∵ a + B = C, ∵ a = C-B, and ∵ B + C = D, C + D = a, a = C-B, ∵ C = - 2b, a = - 3b, d = - B, ∵ a + B + C + D = - 5b, ∵ B is a positive integer, its minimum value is 1, and the maximum value of ∵ a + B + C + D = - 5b is - 5

If a, C, D are integers and B is a positive integer, and a + B = C, B + C = D, C + D = a is satisfied, then the maximum value of a + B + C + D is ()
A. -1B. -5C. 0D. 1

∵ a + B = C, ∵ a = C-B, and ∵ B + C = D, C + D = a, a = C-B, ∵ C = - 2b, a = - 3b, d = - B, ∵ a + B + C + D = - 5b, ∵ B is a positive integer, its minimum value is 1, and the maximum value of ∵ a + B + C + D = - 5b is - 5