A) Tổng số tiền của tất cả tờ mệnh giá 20000 đồng, 10000 đồng và 5000 đồng:

20000 . 3 + 10000 . 4 + 5000 . 6 = 130000 (đồng)

B) Tổng số tiền mệnh giá 2000 đồng:

180000 - 130000 = 50000 (đồng)

a) =20000*3+10000*4+5000*6=130 000 đồng

b) Tổng số tiền mệnh giá 2000 là:

(180000-130000):2000=25 tờ

\(100a+10b+6\)

\(=2\left(50a+5b+3\right)\) hoặc \(10\left(10a+b\right)+6\)

\(3.\left[\left(4-2\right)^2.X+5.2^3\right]-2^3.3=72\\ \Leftrightarrow3.\left[2^2.X+40\right]-24=72\\ \Leftrightarrow3.\left[4X+40\right]=72+24=96\\ \Leftrightarrow4X+40=\dfrac{96}{3}=32\\ \Leftrightarrow4X=32-40=-8\\ Vậy:X=\dfrac{-8}{4}=-2\)

Ta có:

\(Ư\left(35\right)=\left\{\pm1;\pm5;\pm7;\pm35\right\}\\ \Rightarrow\left(2x+1\right),\left(2y-3\right)\in\left\{\left(5,7\right);\left(7,5\right);\left(-5;-7\right);\left(-7,-5\right);\left(1;35\right);\left(35,1\right);\left(-1,-35\right);\left(-35,-1\right)\right\}\\ \Rightarrow\left(x,y\right)\in\left\{\left(2,5\right);\left(3,4\right);\left(-3,-2\right);\left(-4,-1\right);\left(0,19\right);\left(17,2\right);\left(-1,-16\right);\left(-18,1\right)\right\}\)

1: ƯCLN(56;126;266)=14

=>ƯC(56;126;266)={1;-1;2;-2;7;-7;14;-14}

2: ƯCLN(31;22;24)=1

=>ƯC(31;22;24)={1;-1}

3: ƯCLN(105;128;135)=1

=>ƯC(105;128;135)={1;-1}

4: ƯCLN(18;36;45)=9

=>ƯC(18;36;45)={1;-1;3;-3;9;-9}

5: ƯCLN(24;32;64)=8

=>ƯC(24;32;64)={1;-1;2;-2;4;-4;8;-8}

6: ƯCLN(15;25;60)=5

=>ƯC(15;25;60)={1;-1;5;-5}

7: ƯCLN(56;72;128)=8

=>ƯC(56;72;128)={1;-1;2;-2;4;-4;8;-8}

8: ƯCLN(27;54;81)=27

=>ƯC(27;54;81)={1;-1;3;-3;9;-9;27;-27}

9: ƯCLN(18;48;96)=6

=>ƯC(18;48;96)={1;-1;2;-2;3;-3;6;-6}

|a-c|<3

=>-3<a-c<3

|b-c|<2

=>|c-b|<2

=>-2<c-b<2

-3<a-c<3

-2<c-b<2

=>-5<a-c+c-b<3+2

=>-5<a-b<5

=>|a-b|<5

cảm ơn bạn

\(B=3+3^2+3^3+...+3^{118}+3^{119}+3^{120}\\ =\left(3+3^2+3^3\right)+\left(3^4+3^5+3^6\right)+...+\left(3^{118}+3^{119}+3^{120}\right)\\ =3.\left(1+3+3^2\right)+3^4.\left(1+3+3^2\right)+...+3^{118}\left(1+3+3^2\right)\\ =\left(3+3^4+...+3^{118}\right).\left(1+3+3^2\right)\\ =\left(3+3^4+...+3^{118}\right).13⋮13\left(ĐPCM\right)\)

thanks

A=1+2+2^2+...+2^13

=>2A=2+2^2+...+2^14

=>2A-A=2^14-1

=>A=2^14-1

trình bày theo cách lớp 6 được không ạ?

\(a,A=\left\{0;2;4;6;8\right\}\\ b,B=\left\{1;2;3;4;5;6;7;8\right\}\\ c,C=\left\{0;3;6;9;12;15;18\right\}\)

a, A={0;2;4;6;8}

b, B={1;2;3;4;5;6;7;8}

c, C=0;3;6;9;12;15;18}