1, ( - 12 ) - ( 13 - x ) = - 15 - ( - 17 )

=> - 12  - 13 + x = - 15 + 17

=> - 25 + x = 2

=> x = 2 + 25 

=> x = 27 

2, 305 - x + 14 = 48 + ( x - 23 )

=> 305 - x + 14 = 48 + x - 23

=> x + x = 305 + 14 - 48 + 23

=> 2x = 294

=> x = 147

3, - ( x - 6 + 85 ) = ( x + 51 ) - 54

=> - x + 6 - 85 = x + 51 - 54

=> x + x = 6 - 85 - 51 + 54

=> 2x = - 76

=> x = - 38

4, - ( 35 - x ) - ( 37 - x ) = 33 - x

=> - 35 + x - 37 + x = 33 - x

=> x + x + x = 33 + 35 + 37

=> 3x = 105

=> x = 35

1.    x=-27

2.   x=147

3.   x=41

4    x=35 

Câu 1

(-12)-(3-x)=-15-(-17)

-12-3+x=-15+17

-15+x=2

x=17

Câu 2

305-x+14=48+(x-23)

319-x=25+x

2x=294

x=147

các câu còn lại giông nên mk ch đáp án

3,-38

4,35

a ) x = 21 55 ; b ) x = − 11 26 ; c ) x = 11 18 ; d ) x = 1

d ) x = − 1 ; e ) x = 11 7 ; f ) x = 20

Ai lm hộ mk nha

Nhiều quá bạn ơi

1.\(x-43=\left(35-x\right)-48\)

\(\Rightarrow x-43=35-x-48\)

\(\Rightarrow2x=35+43-48\)

\(\Rightarrow2x=30\)

\(\Rightarrow x=15\)

2.\(305-x+14=48+\left(x-23\right)\)

\(\Rightarrow305-x+14=48+x-23\)

\(\Rightarrow305+14=48+x+x-23\)

\(\Rightarrow2x+25=319\)

\(\Rightarrow2x=294\)

\(\Rightarrow x=147\)

3.\(-\left(x-6+85\right)=\left(x+51\right)-54\)

\(\Rightarrow-x+6-85=x+51-54\)

\(\Rightarrow6-85=x+x+51-54\)

\(\Rightarrow2x-3=-79\)

\(\Rightarrow2x=-76\)

\(\Rightarrow x=-38\)

4.\(-\left(35-x\right)-\left(37-x\right)=33-x\)

\(\Rightarrow-35+x-37+x=33-x\)

\(\Rightarrow2x-72=33-x\)

\(\Rightarrow3x=105\)

\(\Rightarrow x=35\)

5.\(13-\left|x\right|=\left|-4\right|\)

\(\Rightarrow13-\left|x\right|=4\)

\(\Leftrightarrow\left[{}\begin{matrix}13-x=4\\13+x=4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=9\\x=-9\end{matrix}\right.\)

a ) x ∈ ± 23 28 . b ) x ∈ − 23 6 ; 35 6 . c ) x ∈ − 17 60 ; 97 60 . d ) x ∈ 67 140 ; 143 140 .

a) \(\dfrac{25}{37}\times\dfrac{18}{29}+\dfrac{18}{29}\times\dfrac{12}{37}\)

\(=\dfrac{18}{29}\times\left(\dfrac{25}{37}+\dfrac{12}{37}\right)\)

\(=\dfrac{18}{29}\times\dfrac{37}{37}\)

\(=\dfrac{18}{29}\times1\)

\(=\dfrac{18}{29}\)

b) \(\dfrac{31}{85}\times\dfrac{11}{19}+\dfrac{31}{85}\times\dfrac{12}{19}-\dfrac{42}{19}\times\dfrac{31}{85}\)

\(=\dfrac{31}{85}\times\left(\dfrac{11}{19}+\dfrac{12}{19}-\dfrac{42}{19}\right)\)

\(=\dfrac{31}{85}\times\dfrac{-19}{19}\)

\(=\dfrac{31}{85}\times-1\)

\(=-\dfrac{31}{85}\)

c) \(\dfrac{16}{53}:\dfrac{17}{9}-\dfrac{16}{53}:\dfrac{17}{8}\)

\(=\dfrac{16}{53}:\left(\dfrac{9}{17}-\dfrac{8}{17}\right)\)

\(=\dfrac{16}{53}:\dfrac{1}{17}\)

\(=\dfrac{16}{901}\)

c) \(\dfrac{1}{5}\times\dfrac{12}{31}\times\dfrac{4}{3}+\dfrac{19}{31}\times\dfrac{4}{15}\)

\(=\dfrac{4}{15}\times\dfrac{12}{31}+\dfrac{19}{31}\times\dfrac{4}{15}\)

\(=\dfrac{4}{15}\times\left(\dfrac{12}{31}+\dfrac{19}{31}\right)\)

\(=\dfrac{4}{15}\times\dfrac{31}{31}\)

\(=\dfrac{4}{15}\times1\)

\(=\dfrac{4}{15}\)

a: =18/29*(25/37+12/37)

=18/29

b: =31/85(11/19+12/19-42/19)

=-31/85

c; =16/53(9/17+8/17)=16/53

d: =4/15(12/31+19/31)=4/15

a)  x − 2 3 = − − 1 5 + 3 4 ⇔ x − 2 3 = − 1 5 + 3 4 = 11 20 ⇔ x − 2 3 = 11 20 x − 2 3 = − 11 20 ⇔ x = 73 60 x = 7 60

b)  x − 3 = 1 5 + 1 7 − 1 14 ⇔ x − 3 = 1 5 + 1 14 = 19 70 ⇔ x − 3 = 19 70 x − 3 = − 19 70 ⇔ x = 229 70 x = 191 70

\(a,\dfrac{x}{4}=\dfrac{15}{20}\\ \Rightarrow\dfrac{x}{4}=\dfrac{3}{4}\\ \Rightarrow x=3\\ b,\dfrac{15}{x}=\dfrac{25}{35}\\ \Rightarrow\dfrac{15}{x}=\dfrac{5}{7}\\ \Rightarrow\dfrac{15}{x}=\dfrac{15}{21}\\ \Rightarrow x=21\\ c,\dfrac{x}{5}=\dfrac{26}{65}\\ \Rightarrow\dfrac{x}{5}=\dfrac{2}{5}\\ \Rightarrow x=2\\ d,\dfrac{3}{x}=\dfrac{51}{85}\\ \Rightarrow\dfrac{3}{x}=\dfrac{3}{5}\\ \Rightarrow x=5\)

a,x4=1520⇒x4=34⇒x=3b,15x=2535⇒15x=57⇒15x=1521⇒x=21c,x5=2665⇒x5=25⇒x=2d,3x=5185⇒3x=35⇒x=5

a) X=27

b) X=8

c) X=-33