a: \(31=31;22=2\cdot11;34=2\cdot17\)

=>\(ƯCLN\left(31;22\right)=1;ƯCLN\left(31;34\right)=1;ƯCLN\left(22;34\right)=2\)

b: \(105=3\cdot5\cdot7;128=2^7;135=3^3\cdot5\)

=>\(ƯCLN\left(105;135\right)=5;ƯCLN\left(128;135\right)=1;ƯCLN\left(105;128\right)=1\)

a)

31 = 31

22=2.11

34=2.17

+) ƯCLN(31,22) = 1

+) ƯCLN(31,34) = 1

+) ƯCLN (22,34) = 2

b)

\(105 = 3.5.7;128 = {2^7};135 = 3.3.3.5 = {3^3}.5\)

+) ƯCLN (105,128) = 1

+) ƯCLN (128,135) = 1

+) ƯCLN (105,135) = 15.

bấm máy tính là ra

ƯCLN(84;105)=21

ƯCLN(16;24)=8

ƯCLN(40;144)=8

ƯCLN(52;42;48)=2

ƯCLN(135;225;405)=45

ƯCLN(128;190;320)=2

a: 84=2^2*3*7; 105=3*5*7

=>ƯCLN(84;105)=3*7=21

b: 16=2^4; 24=2^3*3

=>ƯCLN(16;24)=2^3=8

c: 40=2^3*5; 144=2^3*3^2

=>ƯCLN(40;144)=2^3=8

d: 56=2^3*7; 140=2^2*5*7

=>ƯCLN(56;140)=2^2*7=28

e: 52=2^2*13; 42=2*3*7; 48=2^4*3

=>ƯCLN(52;42;48)=2

f: 135=5*3^3; 225=5^2*3^2; 405=3^4*5

=>ƯCLN(135;225;405)=5*3^2=5*9=45

g: 128=2^7; 190=2*5*19; 320=2^6*5

=>ƯCLN(128;190;320)=2

1)  35.18−5.7.28=−350

2)  45−5(12+9)=−60

1) 35.18-5.7.28

=630-5.7.28

= 630-980

=630+(-980)

=-(980-630)

=-350

1) 35 . 18 - 5 . 7 . 28
= 630 - 35 . 28
= 630 - 980
= -350

2) 45 - 5.(12+9)

= 45-5×21

= 45-105

=-60

3) 31. (-18) + 31. ( - 81) – 31

=31.(-18)+31+81+(-31)

=31.(-18)+[31+ -(31)]+81

câu 5 sai nha

1)  

2)  

1) 35.18-5.7.28

=630-5.7.28

= 630-980

=630+(-980)

=-(980-630)

=-350

X+(27150-135*200):5=53*128+69*128-22*128

X+150:4=12800

X+37,5=12800

X= 12800 - 37,5

X = 12762,5

X+(27150-135*200):5=53*128+69*128-22*128

X + 150 : 4 = 12800

X + 37,5 = 12800

X = 12800 - 37,5

X = 12762,5