15x27 > 4812 : 12 vì 405 > 401

13545 : 43 < 33 x 17 vì 315 < 561

15x27>4812:12

13545:43<33x17

15 x 27 ... 4812 : 12

15 x 27 = 405

4812 : 12 = 401

=> 15 x 27 > 4812 : 12

13545 : 43 ... 33 x 17

13545 : 43 = 315

33 x 17 = 561

=> 13545 : 43 < 33 x 17

a) 42 - x = 5

x = 42 - 5

x = 37

b) 15.(x + 4) = 75

x + 4 = 75 : 15

x + 4 = 5

x = 5 - 4

x = 1

d) x + 18 = 12

x = 12 - 18

x = -6

e) 2x - 15 = -19

2x = (-19) + 15

2x = -4

x = -4 : 2

x = -2

f) 36 : (x^3 - 12) = -3

x^3 - 12 = 36 : (-3)

x^3 - 12 = -12

x^3 = 0

=> x = 0

g)x + 15 = 35

x = 35 - 15

x = 20

h) 2x - 13 = 3^2

2x - 13 = 9

2x = 9 + 13

2x = 22

x = 22 : 2

x = 11

a) 42-x=5

         x=42-5

         x= 37

b)15*(x+4)=75

        x+4=75:15

        x+4=5

        x    =5-4

       x     = 1

a) 42 - x = 5

x = 42 - 5

x = 37

b) 15.(x + 4) = 75

x + 4 = 75 : 15

x + 4 = 5

x = 5 - 4

x = 1

d) x + 18 = 12

x = 12 - 18

x = -6

e) 2x - 15 = -19

2x = (-19) + 15

2x = -4

x = -4 : 2

x = -2

f) 36 : (x^3 - 12) = -3

x^3 - 12 = 36 : (-3)

x^3 - 12 = -12

x^3 = 0

=> x = 0

g)x + 15 = 35

x = 35 - 15

x = 20

h) 2x - 13 = 3^2

2x - 13 = 9

2x = 9 + 13

2x = 22

x = 22 : 2

x = 11

=27.15-27.12-15.27+15.12

=-27.12+15.12

=12.(-27+15)

=12.(-12)

=-144

Cách 2

=27.3-15.15

=81-225

=-144

`a)8^{15}xx4^{13}`

`=2^{45}*2^{26}`

`=2^{71}`

`b)9^{12}xx27^{10}`

`=3^{24}xx3^{30]`

`=3^{54}`

(36 × 27) : 3 = 36 × (27 : 3)

= 36 × 9

= 324

--------

(125 × 15) : 5

= 125 × (15 : 5)

= 125 × 3

= 375

--------

(15 × 12) : 9

= (5 × 3 × 12) : 9

= 5 × (36 : 9)

= 5 × 4

= 20

--------

450 : (3 × 5)

= 450 : 15

= 30

--------

(45 × 63) : 9

= 45 × (63 : 9)

= 45 × 7

= 40 × 7 + 5 × 7

= 280 + 35

= 315

a: \(\dfrac{\left(36\cdot27\right)}{3}=36\cdot\dfrac{27}{3}=36\cdot9=324\)

b: \(\dfrac{\left(125\cdot15\right)}{5}=125\cdot\dfrac{15}{5}=125\cdot3=375\)

c: \(\dfrac{\left(15\cdot12\right)}{9}=\dfrac{3\cdot3\cdot4\cdot5}{9}=4\cdot5=20\)

d: \(\dfrac{450}{3\cdot5}=\dfrac{450}{15}=30\)

e: \(\dfrac{45\cdot63}{9}=\dfrac{45}{9}\cdot63=63\cdot5=315\)

`@` `\text {Ans}`

`\downarrow`

`c)`

`( 34 - 2x ) . ( 2x - 6 ) = 0`

`=>`\(\left[{}\begin{matrix}34-2x=0\\2x-6=0\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}2x=34\\2x=6\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=34\div2\\x=6\div2\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=17\\x=3\end{matrix}\right.\)

Vậy, `x \in {17; 3}`

`d)`

`( 2019 - x ) . ( 3x - 12 ) =0` `?`

`=>`\(\left[{}\begin{matrix}2019-x=0\\3x-12=0\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=2019-0\\3x=12\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=2019\\x=12\div3\end{matrix}\right.\)

`=>`\(\left[{}\begin{matrix}x=2019\\x=4\end{matrix}\right.\)

Vậy, `x \in {2019; 4}`

`e) `

`57 . ( 9x - 27 ) = 0`

`=>`\(9x-27=0\div57\)

`=> 9x - 27 = 0`

`=> 9x = 27`

`=> x = 27 \div 9`

`=> x = 3`

Vậy, `x = 3`

`f)`

`25 + ( 15 - x ) = 30`

`=> 15 - x = 30 - 25`

`=> 15 - x = 5`

`=> x = 15 -5 `

`=> x = 10`

Vậy, `x = 10`

`g) `

`43 - ( 24 - x ) = 20`

`=> 24 - x = 43 - 20`

`=> 24 - x = 23`

`=> x = 24 - 23`

`=> x = 1`

Vậy, `x = 1`

`h) `

`2 . ( x - 5 ) - 17 = 25`

`=> 2 ( x - 5) = 25+17`

`=> 2 ( x - 5) = 42`

`=> x - 5 = 42 \div 2`

`=> x - 5 = 21`

`=> x = 21 + 5`

`=> x = 26`

Vậy, `x = 26`

`i)`

`3 . ( x + 7 ) - 15 = 27`

`=> 3(x + 7) = 27 + 15`

`=> 3(x + 7) = 42`

`=> x +7 = 42 \div 3`

`=> x + 7 = 14`

`=> x = 14 - 7`

`=> x = 7`

Vậy, `x = 7`

`j)`

`15 + 4 . ( x - 2 ) = 95`

`=> 4(x - 2) = 95 - 15`

`=> 4(x - 2) = 80`

`=> x - 2 = 80 \div 4`

`=> x - 2 = 20`

`=> x = 20 + 2`

`=> x = 22`

Vậy, `x = 22`

`k)`

`20 - ( x + 14 ) = 5`

`=> x + 14 = 20 - 5`

`=> x + 14 = 15`

`=> x = 15 - 14`

`=> x = 1`

Vậy, `x = 1`

`l) `

`14 + 3 . ( 5 - x ) = 27`

`=> 3(5 - x) = 27 - 14`

`=> 3(5 - x) = 13`

`=> 5 - x = 13 \div 3`

`=> 5 - x = 13/3`

`=> x = 5- 13/3`

`=> x = 2/3`

Vậy, `x = 2/3.`

`@` `\text {Kaizuu lv uuu}`

nhanh mik tick cho nha

x=-36

x=11

x=100

x=14

x=-36

x=11

x=100

x=14

2: \(\Leftrightarrow\left(\dfrac{x+1}{12}-1\right)+\left(\dfrac{x+2}{13}-1\right)=\left(\dfrac{x+3}{14}-1\right)+\left(\dfrac{x+4}{15}-1\right)\)

=>x-11=0

=>x=11

3: \(\Leftrightarrow\left(\dfrac{x-85}{15}-1\right)+\left(\dfrac{x-74}{13}-2\right)+\left(\dfrac{x-67}{11}-3\right)+\left(\dfrac{x-64}{9}-4\right)=0\)

=>x-100=0

=>x=100

27.(15-12)-15.(27-12)

= 27 . 15 - 27 . 12 - 15 . 27 - 15 . 12

= ( 27 . 15 - 15 . 27 ) - 12. ( 27 - 12 )

= 0 - 12 . 5

= 0 - 60 

= -60

27.(15-12)-15.(27-12)

= 27.15- 27.12 - 15.27 - 15.12

= 27 ( 15-15) - 12( 27-15)

= 27.0 - 12.12

= 0 - 144

= -144

đề là tính à bn