Chọn C

\(124=2^2\cdot31\)

=>\(Ư\left(124\right)=\left\{1;-1;2;-2;4;-4;31;-31;62;-62;124;-124\right\}\)

\(265=5\cdot53\)

=>\(Ư\left(265\right)=\left\{1;-1;5;-5;53;-53;265;-265\right\}\)

\(1236=2^2\cdot3\cdot103\)

=>\(ư\left(1236\right)=\left\{1;-1;2;-2;3;-3;4;-4;6;-6;12;-12;103;-103;206;-206;309;-309;412;-412;618;-618;1236;-1236\right\}\)

\(19197=3^5\cdot79\)

=>\(ư\left(19197\right)=\left\{\text{ 1 ;-1;3;-3; 9;-9; 27 ;-27; 79;-79; 81;-81; 237;-237; 243;-243; 711;-711; 2133;-2133; 6399;-6399; 19197;-19197}\right\}\)

a) 9 - (-2) = 9 + 2 = 11

b) (-7) - 4 = -7+ (-4) = -(7 + 4) = -11

c) 27 - 30 = 27+ (-30) = -(30 – 27) = -3

d) (-63) - (-15) = (-63) + 15 = -(63 -15) = - 48.

a) 24 = 1.24 = 2.12 = 3.8 = 4.6 nên Ư (24) = {l;2;3;4;6;8;12;24}.

b) Tương tự câu a) ta có Ư(63) = {1;3;7;9;21;63}.

c) Ư (30) = {1; 2; 3; 5; 6; 10; 15; 30}.

d) Ư (124) = {1; 2; 4; 31; 62; 124}.

Tương tự 3. HS tự làm

a) 24 = 1.24 = 2.12 = 3.8 = 4.6 nên Ư (24) = {l;2;3;4;6;8;12;24}.

b) Tương tự câu a) ta có Ư(63) = {1;3;7;9;21;63}.

c) Ư (30) = {1; 2; 3; 5; 6; 10; 15; 30}.

d) Ư (124) = {1; 2; 4; 31; 62; 124}

a:

\(33=3\cdot11\)

=> \(Ư\left(33\right)=\left\{1;-1;3;-3;11;-11;33;-33\right\}\)

b: 

\(81=3^4\)

=>\(Ư\left(81\right)=\left\{1;-1;3;-3;9;-9;27;-27;81;-81\right\}\)

c:

\(45=3^2\cdot5\)

 =>\(Ư\left(45\right)=\left\{1;-1;3;-3;5;-5;9;-9;15;-15;45;-45\right\}\)

a, Ư(33)gồm 1,3,11,33

b, Ư(81) gồm 1,3,9,27,81

c,Ư(45) gồm 1,3,5,9,15,45

Tương tự câu 3. HS tự làm

Tương tự 5. HS tự làm