a: \(5\cdot6\cdot7\) ⋮3

\(8\cdot9\) ⋮3

Do đó: \(5\cdot6\cdot7+8\cdot9\) ⋮3

=>Đây là hợp số

b: \(7\cdot11\cdot13\) ⋮7

\(2\cdot5\cdot7\) ⋮7

Do đó: \(7\cdot11\cdot13-2\cdot5\cdot7\) ⋮7

=>Đây là hợp số

c: \(5\cdot11\cdot13\) là số lẻ

\(17\cdot19\cdot23\) là số lẻ

Do đó: \(5\cdot11\cdot13+17\cdot19\cdot23\) là số chẵn

mà \(5\cdot11\cdot13+17\cdot19\cdot23\) <>2

nên đây là hợp số

d: \(1\cdot2\cdot3\cdot\ldots\cdot100=97\cdot1\cdot2\cdot\ldots\cdot96\cdot98\cdot99\cdot100\) ⋮97

\(97\cdot101\cdot103\) ⋮97

Do đó: \(1\cdot2\cdot3\cdot\ldots\cdot100+97\cdot101\cdot103\) ⋮97

=>Đây là hợp số

\(1)2^8:2^4+3^2\cdot3=2^4+3^3=16+27=43\)

\(2)3^{24}:3^{21}+2^2\cdot2^3=3^3+2^5=27+32=59\)

\(3)5^9:5^7+12\cdot3+7^0=5^2+36+1=25+37=62\)

\(4)5^6:5^4+3^2-2021^0=5^2+3^2-1=25+9-1=33\)

\(5)3^{19}:3^{16}+5^2\cdot2^3-1^{2021}=3^3+25\cdot8-1=27+200-1=226\)

\(6)3^6:3^5+2\cdot2^3+2021^0=3^1+2^4+1=3+16+1=20\)

Bài 1:

a: 2x+3=15

=>2x=15-3=12

=>\(x=\frac{12}{2}=6\)

b: 28-3x=13

=>\(3x=28-13=15\)

=>\(x=\frac{15}{3}=5\)

c: \(\left(x-1954\right)\cdot5=50\)

=>x-1954=50:5=10

=>x=10+1954=1964

d: 30(60-x)=30

=>60-x=1

=>x=60-1=59

Bài 2:

a: x+99:3=55

=>x+33=55

=>x=55-33=22

b: (x-25):15=20

=>\(x-25=20\cdot15=300\)

=>x=300+25=325

c: \(7\left(3x-15\right)=42\)

=>\(3x-15=\frac{42}{7}=6\)

=>3x=15+6=21

=>\(x=\frac{21}{3}=7\)

d: \(x\left(x+1\right)=2+4+6+\cdots+2500\)

=>\(x\left(x+1\right)=2\left(1+2+3+\cdots+1250\right)\)

=>\(x\left(x+1\right)=2\cdot1250\cdot\frac{1251}{2}=1250\cdot1251\)

=>\(x^2+x-1250\cdot1251=0\)

=>(x+1251)(x-1250)=0

=>\(\left[\begin{array}{l}x+1251=0\\ x-1250=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=-1251\\ x=1250\end{array}\right.\)

Bài 1:

a: \(46\cdot99=46\cdot\left(100-1\right)=46\cdot100-46\)

=4600-46

=4554

b: \(47\cdot98=47\cdot\left(100-2\right)=47\cdot100-47\cdot2\)

=4700-94

=4604

c: \(18\cdot19=18\left(20-1\right)=18\cdot20-18\)

=360-18

=342

d: \(24\cdot198=24\left(200-2\right)\)

\(=24\cdot200-24\cdot2\)

=4800-48

=4752

Bài 2:

a: \(1800\cdot5=18\cdot100\cdot5=90\cdot100=9000\)

b: \(36\cdot25=25\cdot4\cdot9=100\cdot9=900\)

c: 36600:50=3660:5=732

d: 220000:5000=220:5=44

sạc xong rồi học đk

1: \(3^2\cdot5^3+9^2\)

\(=9\cdot125+81\)

=1125+81

=1206

2: \(55+45:3^2\)

\(=55+45:9\)

=55+5

=60

3: \(8^3:4^2-5^2=64:16-25=4-25=-21\)

4: \(5\cdot3^2-32:2^2=5\cdot9-32:4=45-8=37\)

5: \(16:2^3+5^2\cdot4=16:8+25\cdot4\)

=2+100

=102

6: \(5\cdot2^2-18:3^2\)

\(=5\cdot4-18:9\)

=20-2

=18

7: \(3\cdot5^2-15\cdot2^2=3\cdot25-15\cdot4=75-60=15\)

8: \(2^3\cdot6-72:3^2=8\cdot6-72:9=48-8=40\)

9: \(5\cdot2^2-27:3^2\)

\(=5\cdot4-27:9\)

=20-3

=17

10: \(3\cdot2^4+81:3^2=3\cdot16+81:9=48+9=57\)

11: \(4\cdot5^3-32:2^5=4\cdot125-32:32=500-1=499\)

12: \(6\cdot5^2-32:2^4=6\cdot25-32:16=150-2=148\)

Giúp mình với mng ơi!!

1: \(1026-\left\lbrack\left(3^4+1\right):41\right\rbrack\)

\(=1026-82:41\)

=1026-2

=1024

\(2^{11}:\left\lbrace1026-\left\lbrack\left(3^4+1\right):41\right\rbrack\right\rbrace\)

\(=2^{11}:2^{10}=2\)

2: \(250:\left\lbrace1500:\left\lbrack4\cdot5^3-2^3\cdot25\right\rbrack\right\rbrace\)

\(=250:\left\lbrace1500:\left\lbrack4\cdot125-8\cdot25\right\rbrack\right\rbrace\)

\(=250:\left\lbrace1500:\left\lbrack500-200\right\rbrack\right\rbrace=250:\frac{1500}{3}=250:500=0,5\)

3: \(12+3\cdot\left\lbrace90:\left\lbrack39-\left(2^3-5\right)^2\right\rbrack\right\rbrace\)

\(=12+3\cdot\left\lbrace90:\left\lbrack39-\left(8-5\right)^2\right\rbrack\right\rbrace\)

\(=12+3\cdot\left\lbrace90:\left\lbrack39-3^2\right\rbrack\right\rbrace\)

\(=12+3\cdot\left\lbrace90:\left\lbrack39-9\right\rbrack\right\rbrace\)

\(=12+3\cdot\left\lbrace90:30\right\rbrace=12+3\cdot3=21\)

4: \(24:\left\lbrace390:\left\lbrack500-\left(5^3+49\cdot5\right)\right\rbrack\right\rbrace\)

\(=24:\left\lbrace390:\left\lbrack500-\left(125+245\right)\right\rbrack\right\rbrace\)

\(=24:\left\lbrace390:\left\lbrack500-125-245\right\rbrack\right\rbrace\)

\(=24:\left\lbrace390:\left\lbrack375-245\right\rbrack\right\rbrace\)

\(=24:\left\lbrace390:130\right\rbrace=\frac{24}{3}=8\)

5: \(117:\left\lbrace\left\lbrack79-3\cdot\left(3^3-17\right)\right\rbrack:7+2\right\rbrace\)

\(=117:\left\lbrace\left\lbrack79-3\cdot\left(27-17\right)\right\rbrack:7+2\right\rbrace\)

\(=117:\left\lbrace\left\lbrack79-3\cdot10\right\rbrack:7+2\right\rbrace\)

\(=117:\left\lbrace49:7+2\right\rbrace=\frac{117}{9}=13\)

6: \(514-4\cdot\left\lbrace\left\lbrack40+8\left(6-3\right)^2\right\rbrack-12\right\rbrace\)

\(=514-4\cdot\left\lbrace\left\lbrack40+8\cdot3^2\right\rbrack-12\right\rbrace\)

\(=514-4\cdot\left\lbrace\left\lbrack40+8\cdot9\right\rbrack-12\right\rbrace\)

\(=514-4\cdot\left\lbrace112-12\right\rbrace\)

\(=514-4\cdot100=514-400=114\)

7: \(25\cdot\left\lbrace32:\left\lbrack\left(12-4\right)+4\cdot\left(16:2^3\right)\right\rbrack\right\rbrace\)

\(=25\cdot\left\lbrace32:\left\lbrack8+4\cdot2\right\rbrack\right\rbrace\)

\(=25\cdot\left\lbrace32:16\right\rbrace=25\cdot2=50\)

8: \(30:\left\lbrace175:\left\lbrack355-\left(135+37\cdot5\right)\right\rbrack\right\rbrace\)

\(=30:\left\lbrace175:\left\lbrack355-\left(135+185\right)\right\rbrack\right\rbrace\)

\(=30:\left\lbrace175:\left\lbrack355-320\right\rbrack\right\rbrace=30:\left\lbrace175:35\right\rbrace=\frac{30}{5}=6\)

9: \(32:\left\lbrace160:\left\lbrack300-\left(175+21\cdot5\right)\right\rbrack\right\rbrace\)

\(=32:\left\lbrace160:\left\lbrack300-\left(175+105\right)\right\rbrack\right\rbrace\)

\(=32:\left\lbrace160:\left\lbrack300-280\right\rbrack\right\rbrace\)

\(=32:\left\lbrace160:20\right\rbrace=\frac{32}{8}=4\)

10: \(750:\left\lbrace130-\left\lbrack\left(5\cdot14-65\right)^3+3\right\rbrack\right\rbrace\)

\(=750:\left\lbrace130-\left\lbrack\left(70-65\right)^3+3\right\rbrack\right\rbrace\)

\(=750:\left\lbrace130-\left\lbrack5^3+3\right\rbrack\right\rbrace\)

\(=750:\left\lbrace130-128\right\rbrace=750:2=375\)

Gọi tổng chi phí cho chuyến đi là x(đồng)

(Điều kiện: x>0)

Số tiền mỗi bạn phải đóng ban đầu là \(\frac{x}{40}\) (đồng)

Số tiền mỗi bạn phải đóng thực tế là \(\frac{x}{36}\) (đồng)

Mỗi bạn tham gia còn lại phải đóng thêm 25000 đồng nên ta có:

\(\frac{x}{36}-\frac{x}{40}=25000\)

=>\(\frac{x}{360}=25000\)

=>\(x=25000\cdot360=9000000\) (đồng)

vậy: Tổng chi phí cho chuyến đi là 9000000(đồng)