1: =-2/9(15/17+2/17)=-2/9

2: \(=\dfrac{-6}{3}+\dfrac{-21}{90}\)

=-2-7/30=-67/30

3: \(=\dfrac{3}{4}\cdot\dfrac{7}{5}+\dfrac{9}{7}\cdot\dfrac{3}{2}\)

=21/20+27/14=417/140

4: =-25/13(5/19+14/19)=-25/13

5: =-7/5-45/21=-7/5-15/7=-124/35

1: =-2/9(15/17+2/17)=-2/9

2: =34⋅75+97⋅32=34⋅75+97⋅32

=21/20+27/14=417/140

4: =-25/13(5/19+14/19)=-25/13

5: =-7/5-45/21=-7/5-15/7=-124/35

a) \(\dfrac{2}{3}x-\dfrac{1}{2}=\dfrac{1}{10}\)

\(\dfrac{2}{3}x=\dfrac{1}{10}+\dfrac{1}{2}=\dfrac{3}{5}\)

\(x=\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{9}{10}\)

b) \(\dfrac{39}{7}:x=13\)

\(x=\dfrac{\dfrac{39}{7}}{13}=\dfrac{3}{7}\)

c) \(\left(\dfrac{14}{5}x-50\right):\dfrac{2}{3}=51\)

\(\dfrac{14}{5}x-50=51\cdot\dfrac{2}{3}=34\)

\(\dfrac{14}{5}x=34+50=84\)

\(x=\dfrac{84}{\dfrac{14}{5}}=30\)

d) \(\left(x+\dfrac{1}{2}\right)\left(\dfrac{2}{3}-2x\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+\dfrac{1}{2}=0\\\dfrac{2}{3}-2x=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}\\x=\dfrac{1}{3}\end{matrix}\right.\)

e) \(\dfrac{2}{3}x-\dfrac{1}{2}x=\dfrac{5}{12}\)

\(\dfrac{1}{6}x=\dfrac{5}{12}\)

\(x=\dfrac{5}{12}:\dfrac{1}{6}=\dfrac{5}{2}\)

g) \(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\dfrac{11}{5}-\dfrac{3}{7}=-2\)

\(\left(x\cdot\dfrac{44}{7}+\dfrac{3}{7}\right)\cdot\dfrac{11}{5}=-2+\dfrac{3}{7}=-\dfrac{11}{7}\)

\(x\cdot\dfrac{44}{7}+\dfrac{3}{7}=-\dfrac{11}{7}:\dfrac{11}{5}=-\dfrac{5}{7}\)

\(\dfrac{44}{7}x=-\dfrac{5}{7}-\dfrac{3}{7}=-\dfrac{8}{7}\)

\(x=-\dfrac{8}{7}:\dfrac{44}{7}=-\dfrac{2}{11}\)

h) \(\dfrac{13}{4}x+\left(-\dfrac{7}{6}\right)x-\dfrac{5}{3}=\dfrac{5}{12}\)

\(\dfrac{25}{12}x-\dfrac{5}{3}=\dfrac{5}{12}\)

\(\dfrac{25}{12}x=\dfrac{5}{12}+\dfrac{5}{3}=\dfrac{25}{12}\)

\(x=1\)

Mỏi tay woa bn làm nốt nha!!

a; - \(\dfrac{10}{13}\) + \(\dfrac{5}{17}\) - \(\dfrac{3}{13}\) + \(\dfrac{12}{17}\) - \(\dfrac{11}{20}\)

= - (\(\dfrac{10}{13}\) + \(\dfrac{3}{13}\)) + (\(\dfrac{5}{17}\) + \(\dfrac{12}{17}\)) - \(\dfrac{11}{20}\)

= - 1 + 1  - \(\dfrac{11}{20}\)

=   0 - \(\dfrac{11}{20}\)

= - \(\dfrac{11}{20}\)

b; \(\dfrac{3}{4}\) + \(\dfrac{-5}{6}\) - \(\dfrac{11}{-12}\)

= \(\dfrac{9}{12}\) - \(\dfrac{10}{12}\) + \(\dfrac{11}{12}\)

= \(\dfrac{10}{12}\)

= \(\dfrac{5}{6}\)

c; [13.\(\dfrac{4}{9}\) + 2.\(\dfrac{1}{9}\)] - 3.\(\dfrac{4}{9}\)

= [\(\dfrac{52}{9}\) + \(\dfrac{2}{9}\)] - \(\dfrac{4}{3}\)

= \(\dfrac{54}{9}\) - \(\dfrac{4}{3}\)

= \(\dfrac{14}{3}\)

d; 1,25 : \(\dfrac{15}{20}\) + [25% - \(\dfrac{5}{6}\)] : 4.\(\dfrac{2}{3}\)

= 1,25  x \(\dfrac{20}{15}\) + [\(\dfrac{1}{4}\) - \(\dfrac{5}{6}\)] : 4.\(\dfrac{2}{3}\)

=  \(\dfrac{5}{3}\) - \(\dfrac{7}{12}\) : 4 x \(\dfrac{2}{3}\)

= \(\dfrac{5}{3}\) - \(\dfrac{7}{48}\).\(\dfrac{2}{3}\)

= \(\dfrac{5}{3}\) - \(\dfrac{7}{72}\)

= \(\dfrac{113}{72}\)

1).( 27,56 x 35 ) + ( 27,56 x 67 ) - ( 27,56 x 2)

= (964 + 1846,52) - 55,12

=2810,52 - 55,12

= 2755,4

2).( 4x 35 ) x ( 25 x 5 ) x 2

= ( 140 x 125 ) x2

= 17500 x 2

=35000

4). 3/10

5). 1188

6).  61/6

1)2756   2)35000   3)0   4)3/10   5)10/1/6

1,2755,4

2,35000

3,0

4,\(\frac{3}{10}\)

5,1188

6,\(\frac{61}{6}\)

a) (125 -679 + 145 ) - ( 125 - 679 )=125 -679+145-125+679=145

b)(x - 29 ) - ( 17 - 38 ) = -9

<=> x-29 -17+38=-9

<=>x=-1

c)( x + 5 ) + ( x - 9 ) = x + 2

<=>x+5+x-9=x+2

<=>x+x-x=2+9-5

<=>x=6

d) ( 27 - x )+ ( 15 + x ) = x - 24 

<=> 27-x+15+x-x=-24

<=> -x=-66

<=>x=66

e) -359 + 181 + ( -123 ) + 350 + ( -172 ) =  (181 +350)-(359+172) -123  =531-531-123=-123

f) 13 - 12 + 11 + 10 - 9 + 8 - 7 -6 + 5 - 4 + 3 + 2 -1=( 13 - 12) +11 + (10 - 9)+(8-7)-6+(5-4)+3+(2-1)=1+11+1+1-6+1+3+1=13

a, (125 -679 + 145 ) - ( 125 - 679 )

= 125 - 679 + 145 - 125 + 679 

= ( 125 - 125 ) + ( -679 + 679 ) + 145

= 0 + 0 +145

= 145

b, (x - 29 ) - ( 17 - 38 ) = -9

x - 29 - 17 + 38        = -9

x - 29 - 17                = -9 - 38   

 x - 29 - 17               = -47

x - 29                       = -47 + 17

x - 29                       = -30

x                              = -30 + 29

x                              = -1

Vậy x = -1

c, ( x + 5 ) + ( x - 9 ) = x + 2

x + 5 + x - 9          = x + 2 

x - x + 14              = x + 2 

14                          =  x + 2

x                            = 14 - 2 

x                            = 12

Vậy x = 12

d, ( 27 - x )+ ( 15 + x ) = x - 24 

27 - x + 15 + x         = x - 24

42 + ( -x + x )           = x - 24

42                            = x - 24

x                              = 24 + 42

x                              = 66

Vậy x = 66

e, -359 + 181 + ( -123 ) + 350 + ( -172 ) 

= ( -359 + 350 ) + [ 181 + ( -172 ) ] + ( -123)

= (-9) + 9 + ( -123 )

= 0 + ( -123)

= (-123)

g , 13 - 12 + 11 + 10 - 9 + 8 - 7 -6 + 5 - 4 + 3 + 2 -1

= ( 13 - 12 ) + ( 10 - 9 ) + ( 8 - 7 ) + ( 5 - 4 ) + ( 2 - 1 ) + ( 11 - 6 + 3)

= 1 + 1 + 1 + 1 + 1 + 8

= 1. 5 + 8

= 5 + 8

= 13

3) \(-12+2x-9+x=0\\ -21+3x=0\\ 3x=21\\ x=7\)

4)
\(11+\left(15-x\right)=1\)
\(15-x=1-11\)
\(15-x=-10\)
\(x=15-\left(-10\right)\)
\(x=25\)

5) 
\(4-\left(27-3\right)=x-\left(13-4\right)\)
\(4-24=x-9\)
\(x-9=-20\)
\(x=-20+9\)
\(x=-11\)
 

\(3.-12+\left(2x-9\right)+x=0.\)

\(\Leftrightarrow-12+2x-9+x=0.\Leftrightarrow3x=21.\Leftrightarrow x=7.\)

Vậy \(x=7.\)

\(4.11+\left(15-x\right)=1.\Leftrightarrow11+15-x=1.\Leftrightarrow26-x=1.\Leftrightarrow x=25.\)

Vậy \(x=25.\)

\(5.4-\left(27-3\right)=x-\left(13-4\right).\Leftrightarrow4-24=x-9.\Leftrightarrow-20=x-9.\Leftrightarrow x=-11.\)

Vậy \(x=-11.\)

\(6.8-\left(x-10\right)=23-\left(-4+12\right).\Leftrightarrow8-x+10=23-8.\Leftrightarrow18-x=15.\Leftrightarrow x=3.\)

Vậy \(x=3.\)

\(7.105-5\left(10-5x\right)=-20.\Leftrightarrow105-50+25x=-20.\Leftrightarrow25x=-75.\Leftrightarrow x=-3.\)

Vậy \(x=-3.\)

\(8.\left(x-1\right)\left(8-2x\right)\left(3x+123\right)=0.\)

\(\Leftrightarrow\left[{}\begin{matrix}x-1=0.\\8-2x=0.\\3x+123=0.\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1.\\x=4.\\x=-41.\end{matrix}\right.\)

Vậy \(x\in\left\{1;4;-41\right\}.\)

\(9.\left(x^2-25\right)\left(x+10\right)=0.\)

\(\Leftrightarrow\left(x-5\right)\left(x+5\right)\left(x+10\right)=0.\)

\(\Leftrightarrow\left[{}\begin{matrix}x-5=0.\\x+5=0.\\x+10=0.\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5.\\x=-5.\\x=-10.\end{matrix}\right.\)

Vậy \(x\in\left\{5;-5;-10\right\}.\)

\(10.x\left(x^2+5\right)=0.\Leftrightarrow x=0.\)

a) x = 4

b) x = 3

c) x = 2

d) x = 1

e) x = 3

f) x = 2

g) x = 4

h) x = 3

\(257-\left(3x+25\right)=157\)

\(3x+25=257-157\)

\(3x+25=100\)

\(3x=75\)

\(x=25\)

vay \(x=25\)

\(x-140:35=270\)

\(x-4=270\)

\(x=274\)

vay \(x=274\)

\(23-\left(x:13\right)=18\)

\(\frac{x}{13}=5\)

\(\frac{x}{13}=\frac{65}{13}\)

\(\Rightarrow x=65\)

vay \(x=65\)

\(9\left(x+5\right)-13=671\)

\(9x+45=684\)

\(9x=639\)

\(x=71\)

vay \(x=71\)

\(9\left(4x\right)-13=24\)

\(36x=37\)

\(x=\frac{37}{36}\)

vay \(x=\frac{37}{36}\)

\(\left(x-5\right)-34:17=1\)

\(\left(x-5\right)-2=1\)

\(x-5=3\)

\(x=8\)

vay \(x=8\)

\(\left(2x-7\right).3=3\)

\(2x-7=1\)

\(2x=8\)

\(x=4\)

vay \(x=4\)

\(\left(3x-5\right):2=4.5\)

\(\left(3x-5\right):2=20\)

\(3x-5=10\)

\(3x=15\)

\(x=5\)

vay \(x=5\)

con lai lam tuong tu 

mk moi tay roi nen ban tu lam vay

bạn làm tiếp thì mk đánh 2 tích nữa 

cảm ơn bạn giúp mk