dấu*là gì vậy bạn

Giúp mình nhanh nha.

a, 2.[(-6² + 24) : 4] + 14

= 2.[(36 + 24) : 4] + 14

= 2.(60 : 4) + 14

= 2. 15 + 14

= 30 + 14

= 44

$\frac{14}{17}<\frac{...}{17}<\frac{15}{17}$

Ta gọi tử số cần tìm là $x$ .

Theo bài ra , ta có :

$\frac{14}{17}$ = $\frac{14\times 2}{17\times 2}$ = $\frac{28}{34}$

$\frac{15}{17}$ = $\frac{15\times 2}{17\times 2}$ = $\frac{30}{34}$

$\frac{...}{17}=\frac{x}{34}$

 Vậy : $\frac{28}{34}<\frac{x}{34}<\frac{30}{34}$ nên $x=29$

$\frac{14}{17}<\frac{...}{17}<\frac{15}{17}$

Ta gọi tử số cần tìm là $x$ .

Theo bài ra , ta có :

$\frac{14}{17}$ = $\frac{14\times 2}{17\times 2}$ = $\frac{28}{34}$

$\frac{15}{17}$ = $\frac{15\times 2}{17\times 2}$ = $\frac{30}{34}$

$\frac{...}{17}=\frac{x}{34}$

 Vậy : $\frac{28}{34}<\frac{x}{34}<\frac{30}{34}$ nên $x=29$

a)\(\dfrac{-5}{21}:\dfrac{25}{14}=\dfrac{-5}{21}.\dfrac{14}{25}=\dfrac{-2}{15}\)

b)\(3,4:\dfrac{-17}{14}=\dfrac{17}{15}:\dfrac{-17}{14}=\dfrac{17}{15}.\dfrac{14}{-17}=\dfrac{-14}{15}\)

c) \(\left(-1,7\right):1\dfrac{2}{15}=\dfrac{-17}{10}:\dfrac{17}{15}=\dfrac{-17}{10}.\dfrac{15}{17}=\dfrac{-3}{2}\)

d) \(-8,4:\left(-2,8\right)=\dfrac{-42}{5}:\dfrac{-14}{5}=\dfrac{-42}{5}.\dfrac{5}{-14}=3\)

tick cho mình nhé! 😊

a) \(\left(-15\right)\cdot\left(10-12\right)=\left[\left(-15\right)\cdot10-\left(-15\right)\cdot12\right]=-150+180=30\)

b) \(\left(-17\right)\cdot10-\left(-3\right)\cdot10=\left[-17-\left(-3\right)\right]\cdot10=\left(-17+3\right)\cdot10=-14\cdot10=-140\)

/ (-37) +14+ 26 + 37

= (-37+37) + 14 + 26

= 0 + 14 + 26

= 40

2/ (-24) + 6 + 10+24

= (-24+24) + 6 +10

= 0 + 6 + 10

= 16

3/ 15+23+(-25) + (-23)

= (23-23) + 15 - 25

= 0 + 15 - 25

= -10

4/ 60+33+ (-50) +(-33)

= (33-33) + 60 -50

= 0 + 60 - 50

= 10

5/ (-16) + (-209) + (-14) + 209

= (-209+209) - 16 - 14

= 0 - 16 - 14

= -30

6/ (-12) + (-13) +36 + (-11)

= (-12-13-11) + 36

= -36 + 36

= 0

7/ -16+ 24 + 16-34

= (-16+16) + 24 - 34

= 0 + 24 - 34

= -10

8/ 25+37-48-25-37

= (37-37) + (25-25) - 48

= 0 + 0 - 48

= -48

9/2575+37-2576-29

= (2575-2576) + 37 - 29

= -1 + 37 - 29

= -1- 29 + 37

= -30 + 37

= 7

10/34 +35+36 +37-14-15- 16-17

= (34 - 14) + (35 - 15) + (36 - 16) + (37 - 17) 

= 20 + 20 + 20 + 20

= 20 . 4

= 80

pls t i c k

a) 1-5+7-8+4-1+5-7+8

=(1-1) - (-5+5) -(7-7) -(-8+8) +4

=0

b)=-39+9

=-30

c)=(20-20)-(-4+4)-(8-8)-17+15

=-2

d)= (13-13)-(-98+98)-(91-91)-75

=-75

Ta có :

\(\frac{5}{9}\times\frac{2}{7}=\frac{10}{63};\frac{2}{3}+\frac{5}{6}=\frac{3}{2}\)               \(5-\frac{13}{17}=\frac{72}{17};\frac{9}{11}:\frac{5}{13}=\frac{117}{55}\)

\(5+\frac{9}{14}=\frac{79}{14};\frac{6}{54}:8=\frac{1}{72}\)               \(\frac{24}{72}-\frac{202}{909}=\frac{1}{9};\frac{9}{11}:\frac{5}{13}=\frac{117}{55}\)

Học tốt nha !

#Sơn#

5/9\(\times\)2/7=10/63

2/3+5/6=4/6+5/6=9/6=3/2

5+9/14=70/14+9/14=79/14

6/54:8=1/9:8=1/9\(\times\)1/8=1/72

5-13/17=85/17-13/17=72/17

3:9/10=3\(\times\)10/9=30/9=10/3

24/72-202/909=1/9

9/11:5/13=9/11\(\times\)13/5=117/55

\(\frac{5}{9}\)\(\times\frac{2}{7}\)\(=\frac{5\times2}{9\times7}\)\(=\frac{10}{63}\)

\(\frac{2}{3}\)\(+\frac{5}{6}\)\(=\frac{12+15}{18}\)\(=\frac{27}{18}\)\(=\frac{3}{2}\)

\(5+\frac{9}{14}\)\(=\frac{70+9}{14}\)\(=\frac{79}{14}\)

\(\frac{6}{54}\)\(\div8\)\(=\frac{6}{54}\)\(\times\frac{1}{8}\)\(=\frac{6\times1}{54\times8}\)\(=\frac{6}{432}\)\(=\frac{1}{72}\)

\(5-\frac{13}{17}\)\(=\frac{85-13}{17}\)\(=\frac{72}{17}\)

\(3\div\frac{9}{10}\)\(=3\times\frac{10}{9}\)\(=\frac{3\times10}{9}\)\(=\frac{30}{9}\)\(=\frac{10}{3}\)

\(\frac{24}{72}\)\(-\frac{202}{909}\)\(=\frac{21816-14544}{65448}\)\(=\frac{7272}{65448}\)\(=\frac{1}{9}\)

\(\frac{9}{11}\)\(\div\frac{5}{13}\)\(=\frac{9}{11}\)\(\times\frac{13}{5}\)\(=\frac{9\times13}{11\times5}\)\(=\frac{117}{55}\)

Hok tốt !

Bạn ơi bạn làm đc bao nhiêu thì làm phụ mình nhé 

bài1

a, 

5 - 7 + 3 +(-8)

= -2 + 3 + ( - 8)

=     1    + (-8)= -7

a; - (-5) - (+7) + (+3) + (-8)

  = 5 - 7 + 3  - 8

= (5 + 3 - 8) - 7

= (8 - 8) - 7

= 0 - 7

= - 7

17 - 2x = -15

2x = 17 - (-15)

2x = 32

x = 32 : 2

x = 16

--------

54 : (x + 2) = -6

x + 2 = 54 : (-6)

x + 2 = -9

x = -9 - 2

x = -11

--------

12.(3 - x) = 72

3 - x = 72 : 12

3 - x = 6

x = 3 - 6

x = -3

-------

-3(x + 5) + 18 = -27

-3(x + 5) = -27 - 18

-3(x + 5) = -45

x + 5 = -45 : (-3)

x + 5 = 15

x = 15 - 5

x = 10

-------

(x + 5)² = 9

x + 5 = 3 hoặc x + 5 = -3

*) x + 5 = 3

x = 3 - 5

x = -2

*) x + 5 = -3

x = -3 - 5

x = -8

Vậy x = -8; x = -2

--------

(3 - x)³ = 27

(3 - x)³ = 3³

3 - x = 3

x = 3 - 3

x = 0

=00

- 3\(x\) + 24  = -24

  3\(x\)          = 24 + 24

   3\(x\)          = 48

     \(x\)           = 48 : 3

     \(x\)           = 16