a) 5x - 14 = x - 34

5x - x = -34 + 14

4x = -20

x = -20 : 4

x = -5

b) x - 3 - (3x + 2) = -15

x - 3 - 3x - 2 = -15

x - 3x = -15 + 3 + 2

-2x = -10

x = (-10) : (-2)

x = 5

c) 2(x  - 12) + 19 = x + (-34)

2x - 24 + 19 = x + (-34)

2x - x = -34 + 24 - 19

x = -29

d) 2(x - 33) - 3(x - 43) = 96 - 115

2x - 66 - 3x + 129 = 96 - 115

2x - 3x = 96 - 115 + 66 - 129

-x = -82

x = 82

e) 2x + 3 - 9x = -11

2x - 9x = -11 - 3

-7x = -14

x = (-14) : (-7)

x = 2

f) -(x + 3 - 84) = (x + 70 - 71) - 6

-x - 3 + 84 = x + 70 - 71 - 6

-x - x = 70 - 71 - 6 - 84

-2x = -91

x = (-91) : (-2)

x = 45,5

\(1,\Leftrightarrow7x=42\Leftrightarrow x=6\\ 2,\Leftrightarrow36-4x=4\Leftrightarrow4x=32\Leftrightarrow x=8\\ 3,\Leftrightarrow3x=35\Leftrightarrow x=\dfrac{35}{3}\\ 4,\Leftrightarrow x-12=144\Leftrightarrow x=156\\ 5,\Leftrightarrow x-14=16\Leftrightarrow x=30\\ 6,\Leftrightarrow3x-24=\dfrac{148}{73}\Leftrightarrow3x=\dfrac{1900}{73}\Leftrightarrow x=\dfrac{1900}{219}\\ 7,\Leftrightarrow33+x=45\Leftrightarrow x=12\\ 8,Sai.đề\\ 9,\Leftrightarrow\left(x+9\right):2=39\Leftrightarrow x+9=78\Leftrightarrow x=69\\ 11,\Leftrightarrow2\left(x+7\right)=38\Leftrightarrow x+7=19\Leftrightarrow x=12\\ 13,\Leftrightarrow2\left(x-51\right)=66\Leftrightarrow x-51=33\Leftrightarrow x=84\)

\(15,\Leftrightarrow x-19=9\Leftrightarrow x=28\\ 17,\Leftrightarrow\left(x-3\right):2=48\Leftrightarrow x-3=96\Leftrightarrow x=99\\ 19,\Leftrightarrow0x=46\Leftrightarrow x\in\varnothing\\ 8,Sai.đề\\ 14,\Leftrightarrow2x=209\Leftrightarrow x=\dfrac{209}{2}\\ 16,\Leftrightarrow2x+6=157\Leftrightarrow2x=151\Leftrightarrow x=\dfrac{151}{2}\\ 18,\Leftrightarrow5\left(x+4\right)=100\Leftrightarrow x+4=20\Leftrightarrow x=16\\ 20,\Leftrightarrow\left(3x-5\right)^3=27=3^3\Leftrightarrow3x-5=3\Leftrightarrow x=\dfrac{8}{3}\)

a) 125⁴:25³= (5³)³: (5²)³=5⁹:5⁶=5³

b) 4¹⁴:5²⁸=4¹⁴: 5^2.14=4¹⁴:(5²)¹⁴= 4¹⁴:25¹⁴

c) 12ⁿ:2²ⁿ= 

a)\(\frac{7}{13}.\frac{7}{15}-\frac{5}{12}.\frac{21}{39}+\frac{49}{21}.\frac{8}{15}\)

=\(\frac{7}{13}.\frac{7}{15}-\frac{5}{12}.\frac{7}{13}+\frac{7}{13}.\frac{8}{15}\)

=\(\frac{7}{13}.\left(\frac{7}{15}-\frac{5}{12}-\frac{8}{15}\right)\)

=\(\frac{7}{13}.\frac{7}{12}\)

=\(\frac{49}{156}\)

b)\(\left(\frac{12}{199}+\frac{23}{200}-\frac{34}{201}\right).\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\)

=\(a.\left(\frac{3}{6}-\frac{2}{6}-\frac{1}{6}\right)\)

=a . 0

=0

Bài 2

a)Có

\(3^{200}=3^{2.100}=\left(3^2\right)^{100}=9^{100}\)

\(2^{300}=2^{3.100}=\left(2^3\right)^{100}=8^{100}\)

Vì 8<9 =>\(8^{100}< 9^{100}\) =>\(3^{200}>2^{300}\)

câu c bạn so sành với phân số trung gian là 1

1a) 25 .8 - 12.5 + 272 :17 - 8

= 200 -  60 + 16 - 8

= 140+16-8

= 156 - 8

= 148

b) 125: 25 +14 - 142 : 71

= 5 + 14 - 2 

= 19 - 2 = 17

c) 13. 17 - 256: 16 + 14 : 7 - 1

= 221 - 16 + 2 - 1 

= 205 + 2 - 1 

= 207 - 1 = 206

d) 15 . 24 - 14 . 5 (145 : 5 - 27)

= 360 - 70 (29- 27)

= 360 - 70 . 2

= 360 - 140

= 220

2a) 37 + x = 55

               x= 55 - 37

               x = 18

b) x- 31 = 24

     x       = 24 + 31

     x        = 55

c) 21 (x-11) = 21

        x - 11   = 21 : 21

          x        = 1 +11

           x       = 12

d ) 9. (x - 29)= 0

           x - 29 = 0 :9

             x       = 29

e) (x - 1954) . 5 = 50

         x - 1954   = 50 : 5

          x             = 1964

f ) 30 . 60 - x = 30

        1800 - x   = 30

             x        = 1800 - 30

             x        = 1770

Viết mỏi tay quá huhuh

Cảm ơn nghen

thanks bn nhé

A.35 x 34 + 35 x 38 + 65 x 75 + 65 x 45

Câu này không tính hợp lí được

B. 12x 53 + 53 x 172 - 53 x 84

= 53 x (12 + 172 - 84)

= 53 x 100

= 5300

C. 36 x 28 + 36 x 82 + 64 x 69 + 64 x 41

= 36 x (28+82) + 64 x (69+41)

= 36 x 110 + 64 x 110

= (36+64) x 110

= 100 x 110

= 11 000

D. A = 1+2+3+...+100

= (1+ 100) x 50

= 101 x 50

= 5050

E. B =17+19+...+101+103

= (103 +17) x [(103 - 17):2 + 1]

= 120 x 44

=5280

G. D= 3x (12+13+14+15) + 3x(8+7+6+5)

= 3 x (5+6+7+8+12+13+14+15)

= 3 x (20 x 4)

= 3 x 80

=240

a) 10320

b) 5300

c) 11000

d) 5050

e) 2460

g)  240