\(\dfrac{18\times35\times17}{34\times25\times9}=\dfrac{9\times2\times5\times7\times17}{17\times2\times5\times5\times9}=\dfrac{7}{5}\)

\(\dfrac{18\text{×}35\text{×}17}{34\text{×}25\text{×}9}\)\(=\)\(\dfrac{7}{5}\)

\(=\dfrac{7}{5}=1,4\)

1)tính

a)\(-17+\left(-19\right)+25\)

\(=-17-19+25\)

\(=-\left(17+19\right)+25\)

\(=-36+25\)

\(=-\left(36-25\right)\)

\(=-11\)

b)\(-26+\left(-25\right)-18\)

\(=-26-25-18\)

\(=-\left(26+25\right)-18\)

\(=-51-18\)

​\(=-\left(51+18\right)\)​

\(=-69\)

c)\(35-\left(-19\right)-19-8\)

\(=35+19-19-8\)

\(=35+\left(19-19\right)-8\)

\(=35+0-8\)

\(=35-8\)

\(=27\)

d)\(1963-\left(-180\right)-1990\)

\(=1963+180-1990\)

\(=2143-1990\)

\(=153\)

2)Tìm x thuộc z biết

a)\(x-\left(-18\right)=25+\left(-17\right)\)

\(\Leftrightarrow x+18=25-17\)

\(\Leftrightarrow x+18=8\)

\(\Leftrightarrow x=8-18\)

\(\Leftrightarrow x=-10\)

Vậy x=-10

b)\(x-28=-27-30\)

\(\Leftrightarrow x-28=-\left(27+30\right)\)

\(\Leftrightarrow x-28=-57\)

\(\Leftrightarrow x=-57+28\)

\(\Leftrightarrow x=-\left(57-28\right)\)

\(\Leftrightarrow x=-29\)

Vậy x=-29

c)\(35-\left(-x\right)=27-18-\left(-8\right)\)

\(\Leftrightarrow35+x=27-18+8\)

\(\Leftrightarrow35+x=9+8\)

\(\Leftrightarrow35+x=17\)

\(\Leftrightarrow x=17-35\)

\(\Leftrightarrow x=-18\)

Vậy x=-18

d)\(40+\left(-x\right)=35-\left(-27\right)\)

\(\Leftrightarrow40-x=35+27\)

\(\Leftrightarrow40-x=62\)

\(\Leftrightarrow x=40-62\)

\(\Leftrightarrow x=-22\)

Vậy x=-22

\(\left(x+\frac{1}{5}\right)^2+\frac{17}{25}=\frac{26}{25}\)

\(\left(x+\frac{1}{5}\right)^2=\frac{26}{25}-\frac{17}{25}\)

\(\left(x+\frac{1}{5}\right)^2=\frac{9}{25}=\left(\frac{3}{5}\right)^2=\left(-\frac{3}{5}\right)^2\)

\(\Rightarrow x+\frac{1}{5}=\frac{3}{5}\)                                             \(\Rightarrow x+\frac{1}{5}=-\frac{3}{5}\)

\(x=\frac{3}{5}-\frac{1}{5}\)                                                      \(x=-\frac{3}{5}-\frac{1}{5}\)

\(x=\frac{2}{5}\)                                                                   \(x=\frac{-4}{5}\)

                                       \(vậy...\)

1: =>x=8-35=-27

2: =>15-4+x=6

=>x+11=6

hay x=-5

3: =>-30+25-x=-1

=>x+5=1

hay x=-4

4: =>x-(-13)=-8

=>x+13=-8

hay x=-21

5: =>x-29-17+38=-9

=>x-8=-9

hay x=-1

a: =>5-x=-23

=>x=5+23=28

b: =>x-3-x+7-25+x=54

=>x-21=54

=>x=75

c: =>7-9x-2x+4=-5x-35+27-25=-5x-37

=>-11x+3=-5x-37

=>-6x=-40

=>x=20/3

a) \(10-x-5=\left(-5\right)-7-11\)

\(\Rightarrow5-x=-23\)

\(\Rightarrow x=5+23\)

\(\Rightarrow x=28\)

b) \(\left(x-3\right)-\left(x+17-24\right)-\left(25-x\right)=24-\left(-30\right)\)

\(\Rightarrow x-3-x-17+24-25+x=54\)

\(\Rightarrow x-21=54\)

\(\Rightarrow x=54+21\)

\(\Rightarrow x=75\)

c) \(\left(7-9x\right)-\left(2x-4\right)=-\left(5x+35\right)-\left(-27\right)-25\)

\(\Rightarrow7-9x-2x+4=-5x-35+27-25\)

\(\Rightarrow11-11x=-5x-33\)

\(\Rightarrow-11x+5x=-33-11\)

\(\Rightarrow-6x=-22\)

\(\Rightarrow x=\dfrac{22}{6}=\dfrac{11}{3}\)

a. 
10-x-5 = (-5) - 7 -11
=>5-x = 0
=>x=5
b
(x-3) - (x+17-24) - (25-x) = 24 - (-30)
=>x - 3 - x - 17 + 24 - 25 - x = 24 + 30
=>-x - 21 = 54
=>-x = 75
=>x = -75
c
(7 - 9x) - (2x - 4) = - (5x + 35) - (-27) - 25
=>7-9x - 2x + 4 = -5x - 35 + 27 - 35
=>11 - 11x + 5x = -43
=>16x = 11 + 43
=>16x = 54
=>x=4

b) Thay x=-28

\(\left(-2\right)+17+\left(-28\right)=-13\)

c) Thay x=-4

\(\left(-4\right)+25+\left(-47\right)=-26\)

d) Thay x=8

\(25+8+\left(-13\right)=20\)

a ) x = 25 28 b ) x = 5 12 .

c) x= 1             d) x = 17

a; \(x\) - \(\dfrac{3}{4}\) = \(\dfrac{1}{7}\)

    \(x\)        = \(\dfrac{1}{7}\) + \(\dfrac{3}{4}\)

    \(x\)       =  \(\dfrac{4}{28}\) + \(\dfrac{21}{28}\)

    \(x\)       =  \(\dfrac{25}{28}\)

Vậy \(x=\dfrac{25}{28}\) 

b; - \(x\) + \(\dfrac{3}{5}\) + \(\dfrac{13}{20}\) = \(\dfrac{5}{6}\)

     (\(\dfrac{12}{20}\) + \(\dfrac{13}{20}\))  - \(x\) = \(\dfrac{5}{6}\)

    \(\dfrac{5}{4}\) - \(x\)  = \(\dfrac{5}{6}\) 

           \(x\) = \(\dfrac{5}{4}\) - \(\dfrac{5}{6}\)

           \(x\) = \(\dfrac{30}{24}\) -  \(\dfrac{20}{24}\)

            \(x\) = \(\dfrac{5}{12}\)

Vậy \(x=\dfrac{5}{4}\) 

1.

(x + 1/5)² = 26/25 - 17/25 

(x + 1/5)² = 9/25 

Rút căn hai vế : 

|(x + 1/5)| = 3/5 

x = -4/5 
hoặc
x = 2/5

2.

(x + 2) / 327 + (x + 3) / 326 + (x + 4) / 325 + (x + 5) / 324 + (x + 349) / 5 = 0 
<=> (x + 2) / 327 +1+ (x + 3) / 326 +1+ (x + 4) / 325 +1+ (x + 5) / 324 +1+ (x + 349) / 5 -4 = 0 
<=> (x+ 329)/327 + (x+ 329)/326 + (x+ 329)/325 + (x+ 329)//324 + (x+ 329)/5 =0 
<=> (x+ 329).(1/327 + 1/ 326 + 1/325 + 1/324 +1/5) =0 
Do (1/327 + 1/ 326 + 1/325 + 1/324 +1/5) >0 nên x+ 329 =0 => x= -329 

Câu 1 chưa chắc đã đúng ( quên hết kiến thức lớp 6 rùi ) hihi

aaaaaaaa . chết rồi . cho mình sủa câu thứ nhất :

(x+1/5)² + 17/25=26/25

( x + 1/5 ) ² = 26/25 - 17/25

( x + 1/5 ) ² = 3/5²

x + 1/5 = 3/5

x = 2/5.