77. the necessary nd saunflicicnt condition that congruence ax + by cu0 (mod m) has solution if: (a) dle (c) dle when d- (a, b, m) (8) d-(a, b, m) (d) none of t

77. The necessary nd saunflicicnt condition that congruence ax + by cu0 (mod m) has solution if: (A) dle (C) dle when d- (a, b, m) (8) d-(a, b, m) (D) None of these 78. Congruence relations are (A) Rellexive (B) Symmetrie (C)Bodh (A) and (B) (D) None of these 79. The function f(x)= |xl is . (A) continuous (B) not continuous (C) differentiable (D) None of these 80. Derivative of constant fiunction is (A) 0 (B) (C) 2 (D) None of these 81. A bounded function, having a finite number of points of discontinuity on la, b), is g. on [a, b] (A) integrable (B) not integrable (C) differentiable (D) None of these 82. An arithmetic function fis said to be iff (mn)-f (on) f n), where (1, 1)1. (A) homomorphic (B) multiplicative (C) holomorphie (D) None of these 83. Iffis a multiplicative funetion and S() fd) S(m, then: diw (B) inverse off (A) multiplicative (C) isomorhic (D) None of these