Find the values of a and b for which the following system of equations has infinitely many solutions:
(i) (2a - 1) x - 3y = 5
3x + (b - 2) y = 3
(ii) 2x - (2a + 5) y = 5
(2b + 1) x - 9y = 15
(iii) (a - 1) x + 3y = 2
6x + (1 - 2b) y = 6
(iv) 3x + 4y = 12
(a + b) x + 2 (a - b) y = 5a - 1
(v) 2x + 3y = 7
(a - b) x + (a + b) y = 3a + b - 2
(vi) 2x + 3y - 7 = 0
(a - 1) x + (a + 1) y = (3a - 1)
(vii) 2x + 3y = 7
(a - 1) x + (a + 2) y = 3a
(viii) x + 2y = 1
(a - b) x + (a + b) y = a + b - 2
(ix) 2x + 3y = 7
2ax + ay = 28 - by
(i) a = 3, b = 15
(ii) a = -1, b = 52
(iii) a = 3, b = -4
(iv) a = 5, b = 1
(v) a = 5, b = 1
(vi) a = 5
(vii) a = 7
(viii) a = 3, b = 1
(ix) a = 4, b =8