a, 46*42+46*5+23*2*10+46*42+46=46*(42+5+10+42+1)=46*100=4600

b,5/3*1/9+5/3*5/9+5/3*7/9-5/3*4/9=5/3*(1/9+5/9+7/9-4/9)=5/3*1=5/3

a) 46 x 42 + 46 x 5 + 23 x 2 x 10 + 46 x 42 + 46

= 46 x 42 + 46 x 5 + 46 x 10 + 46 x 42 + 46

= 46 x (42 + 5 + 10 + 42 + 1)

= 46 x 100

= 4600

b) \(\frac{5}{3}\times\frac{1}{9}+\frac{5}{3}\times\frac{5}{9}+\frac{5}{3}\times\frac{7}{9}-\frac{5}{3}\times\frac{4}{9}\)

\(=\frac{5}{3}\times\left(\frac{1}{9}+\frac{5}{9}+\frac{7}{9}-\frac{4}{9}\right)\)

\(=\frac{5}{3}\times1\)

\(=\frac{5}{3}\)

\(a;46\times42+46\times5+23\times2\times10+46\times42+46\)

\(=46\times\left(42+5+10+42+1\right)\)

\(=46\times100=4600\)

A = \(\frac{40}{31\cdot39}+\frac{35}{39\cdot46}+\frac{30}{46\cdot52}+\frac{25}{52\cdot57}\)

A= \(5.\left(\frac{8}{31\cdot39}+\frac{7}{39\cdot46}+\frac{6}{46\cdot52}+\frac{5}{52\cdot57}\right)\)

A= \(5\cdot\left(\frac{1}{31}-\frac{1}{39}+\frac{1}{39}-\frac{1}{46}+\frac{1}{46}-\frac{1}{52}+\frac{1}{52}-\frac{1}{57}\right)\)

A= \(5.\left(\frac{1}{31}-\frac{1}{57}\right)\)

A= \(5.\left(\frac{26}{1767}\right)\)

A = \(\frac{130}{1767}\)

a: \(\dfrac{-35}{-7}=\dfrac{35}{7}=5\)

b: \(\dfrac{42}{-21}=-\dfrac{42}{21}=-2\)

c: \(\dfrac{55}{-5}=-\dfrac{55}{5}=-11\)

d: \(\dfrac{46}{-23}=-\dfrac{46}{23}=-2\)

e: \(-30:\left(-2\right)=\dfrac{30}{2}=15\)

f: \(23\cdot\left(-4\right)=-23\cdot4=-92\)

g: \(15\cdot\left(-3\right)\cdot0=15\cdot0=0\)

h: \(-32\cdot14=-32\cdot10-32\cdot4=-320-128=-448\)

45-58+(-45)+(+58)-3=45-58-45+58-3=(45-45)+(58-58)-3=-3

(-57)-(-12)+3-(-57)=-57+12+3+57=(-57+57)+12+3=15

-(-24)-(-30)+(-24)-30+8=24+30-24-30+8=(24-24)+(30-30)+8=8

-(-12)+(+19)-(+12)+8-19=12+19-12+8-19=(12-12)+(19-19)+8=8

47-(-53)+(-47)-(+53)=47+53-47-53=(47-47)+(53-53)=0

-(+28)+32-(-28)+(-34)=-28+32+28-34=(-28+28)-(34-32)=-2

15-(+72)+(-15)+(+72)=15-72-15+72=(15-15)+(72-72)=0

20-(+46)+(-25)-(-46)=20-46-25+46=(20-25)+(46-46)=-5

28-(-32)+(-28)-32+5=28+32-28-32+5=(28-28)+(32-32)+5=5

-75+(-49)+(+75)+49-12=-75-49+75+49-12=(-75+75)+(49-49)-12=-12

\(...=45-58-45+58-3=-3\)

\(...=-57+12+3+57=15\)

\(...=24+30-24-30+8=8\)

\(...=12+19-12+8-19=8\)

\(...=47+53-47-53=0\)

\(...=-28+32+28-34=-2\)

\(...=15-72-15+72=0\)

\(...=20-46-25+46=-5\)

\(=...28+32-28-32+5=5\)

\(...=-75-49+75+49-12=-12\)

a) 8 000 + 7 000

Nhẩm: 8 nghìn + 7 nghìn = 15 nghìn

Vậy 8 000 + 7 000 = 15 000

16 000 – 9 000

Nhẩm: 16 nghìn – 9 nghìn = 7 nghìn

Vậy 16 000 – 9 000 = 7 000

25 000 + 30 000

Nhẩm: 25 nghìn + 30 nghìn = 55 nghìn

Vậy 25 000 + 30 000 = 55 000

b) 46 000 + 4 000 + 9 000 = 50 000 + 9 000 = 59 000

73 000 – 3 000 – 50 000 = 70 000 – 50 000 = 20 000

32 000 + 5 000 – 17 000 = 37 000 – 17 000 = 20 000

\(5^{30}>3^{46}\)

5^30=(5^2)^15=(5^2)^3^5

3^46=(3^2)^23=(3^2)^21.3.3=(3^2)^3^7.3.3

Vì 3^7.3.3 >3^5

Nên 5^30<3^46

Kí hiệu này là cách viết tắt của mũ ^

Ta có : 5 ^ 30 = ( 5 ^ 2 ) ^ 15 = 25 ^ 15 

         3 ^ 45 = ( 3 ^ 3 ) ^ 15 = 27 ^ 15 

Vì 25 ^ 15 < 27 ^ 15 nên 5 ^ 30 < 3 ^ 45 

Mà 3 ^ 45 < 3 ^ 46

Nên 5 ^ 30 < 3 ^ 46

12Al + 46HNO₃ --> 12Al(NO₃)₃ + 4NO + 3N₂O + 23H₂O

=> D

2Fe₃O₄ + 10H₂SO₄ --> 3Fe₂(SO₄)₃ + SO₂ + 10H₂O

=> B