Prove of disprove that if A, B and C are integers and the product BC is evenly divisible by A then either B is evenly divisible by A or C is evenly divisible by A.
On the contrary, assume that neither B is divisible by A nor C is divisible by A.
So, A doesn't divide B & A doesn't divide C
It implies, A doesn't divide B.C, which is a contradiction as A divides BC.
So, if A divides BC then either A divides B or A divides C.
Prove of disprove that if A, B and C are integers and the product BC is...
(1) Prove or disprove the following statements. (a) Let a, b and c be integers. If aſc and b|c, then (a + b)|c (b) Let a, b and c be integers. If aſb, then (ac)(bc)
1. Let a, b,cE Z be positive integers. Prove or disprove each of the following (a) If b | c, then gcd(a, b) gcd(a, c). (b) If b c, then ged(a., b) < gcd(a, c)
Prove or disprove the following expression. (Prove: using Boolean algebra. Disprove: using truth table.) (NOT is presented by -.) 1. a + b (c^- + d)^- = a^-b^- + a^-cd^- 2. ab^- + bc^- + ac^- = (a + b + c) (a^- + b^-+ c^-) 3. a^- + bd^-^- (c + d) + ab^-d = ac^-d + ab^-cd + abd
prove it by counterpositive
4.52 Let n and m be integers. If nm is not evenly divisible by 3, then neither n nor m is evenly divisible by 3. (In fact, the converse is true too, but you don't have to prove it.)
HELPPPP!!!! sepcific
explanation is best !!! this is discrete mathematics content.
1. Prove, or disprove by finding a counterexample: If a|bc where a,b and c are positive integers then a b or a c. 2. Let n be an odd integer. Show that there is an integer k such that n2 = 8k +1.
10. Let A, B, and C be sets. (a) Prove or disprove: if A - C CB-C, then ACB. (b) State the converse of part (a) and prove or disprove.
(a) If a | bc, show that a | b*gcd(a,c). (b) If a, b are coprime integers and c | at and c | bt, show that c | t. (c) If a, b, c are integers with a, c coprime, prove that gcd(ab, c) = gcd(b, c).
(6) Use a proof by contrapositive to prove for all integers a, b and c, if a t be then à f 6. (7) Prove using cases that the square of any integer has the form 4k or 4k +1 for some integer k. (8) Prove by induction that 32n -1 is divisible by 8.
22. Prove: if a, b, and c are odd, and a | b - c and a bc, then a | b and a c
22. Prove: if a, b, and c are odd, and a | b - c and a bc, then a | b and a c
6. Prove that if a and b are odd integers, then a2 is divisible by 8. 7. Prove that if a is an odd integer, then ta + (a + 2)?+ (a +4)2 +1) is divisible by 12.