-25-x-5=145+5x-680

-30-x=5x-535

4x=-565 x=-141,25

Ta có: \(\dfrac{x-25}{75}+\dfrac{x-15}{85}+\dfrac{x-5}{95}+\dfrac{x-145}{15}=0\)

\(\Leftrightarrow\dfrac{x-25}{75}-1+\dfrac{x-15}{85}-1+\dfrac{x-5}{95}-1+\dfrac{x-145}{15}+3=0\)

\(\Leftrightarrow\dfrac{x-100}{75}+\dfrac{x-100}{85}+\dfrac{x-100}{95}+\dfrac{x-100}{15}=0\)

\(\Leftrightarrow\left(x-100\right)\left(\dfrac{1}{75}+\dfrac{1}{85}+\dfrac{1}{95}+\dfrac{1}{15}\right)=0\)

mà \(\dfrac{1}{75}+\dfrac{1}{85}+\dfrac{1}{95}+\dfrac{1}{15}>0\)

nên x-100=0

hay x=100

Vậy: S={100}

⇔ 4X - 3304/323 = 0

⇔ X=3304/323/4

⇔ X=826/323

a)

x × 1 1 2 = 1 4 5 − 2 5 x × 3 2 = 9 5 − 2 5 x × 3 2 = 7 5 x = 7 5 : 3 2 x = 14 15

b)

x × 0 , 75 + x × 0 , 25 = 5 x × 0 , 75 + 0 , 25 = 5 x × 1 = 5 x = 5 : 1 x = 5

=>x+25=425/6-5/6x

=>11/6x=275/6

=>x=25

\(\Leftrightarrow\) x + 25= \(\dfrac{425}{6}\) - \(\dfrac{5}{6}\)x

\(\Leftrightarrow\) x + \(\dfrac{5}{6}\)x= \(\dfrac{425}{6}-25\)

\(\Leftrightarrow\) \(\dfrac{11}{6}\)x= \(\dfrac{275}{6}\)

\(\Leftrightarrow\) x= 25

 `x + 25 = 5/6 (85 - x)`

`=> x + 25 =425/6 - (5x)/6`

`=> x + (5x)/6=425/6-25`

`=> 11x/6 = 275/6`

`=> 11x=275`

`=>x= 275:11`

`=>x= 25`

Trả lời:

\(194-24\div\left(44x-3\right)-25=145\)

\(\Leftrightarrow194-24\div\left(44x-3\right)=170\)

\(\Leftrightarrow24\div\left(44x-3\right)=24\)

\(\Leftrightarrow44x-3=1\)

\(\Leftrightarrow44x=4\)

\(\Leftrightarrow x=\frac{1}{11}\)

Vậy \(x=\frac{1}{11}\)

\(x\times\frac{1}{3}\div\frac{2}{9}-x\div5=1\frac{2}{5}\)

\(\Leftrightarrow x\times\frac{1}{3}\times\frac{9}{2}-x\times\frac{1}{5}=\frac{7}{5}\)

\(\Leftrightarrow x\times\frac{3}{2}-x\times\frac{1}{5}=\frac{7}{5}\)

\(\Leftrightarrow x\times\left(\frac{3}{2}-\frac{1}{5}\right)=\frac{7}{5}\)

\(\Leftrightarrow x\times\frac{13}{10}=\frac{7}{5}\)

\(\Leftrightarrow x=\frac{14}{13}\)

Vậy \(x=\frac{14}{13}\)

lp 5 chua hoc 4x moi chi hoc 44 *  x thui nha!

194-24:(44×x-3)=145+25

194-24:(44×x-3)=170

24:(44×x-3)=194-170

24:(44×x-3)=24

(44×x-3)=24:24

(44×x-3)=1

44×x=1+3

44×x=4

x=4:44

x=1/11

vậy x=1/11

a) đề bài => \(\frac{159-x}{141}+1+\frac{157-x}{143}+1+...+\frac{151-x}{149}+1=0\)

=>\(\frac{300-x}{141}+\frac{300-x}{143}+...+\frac{300-x}{149}=0\)

=>\(\left(300-x\right).\left(\frac{1}{141}+\frac{1}{143}+...+\frac{1}{149}\right)=0\)

vì \(\frac{1}{141}+\frac{1}{143}+...+\frac{1}{149}\ne0\)

=> \(300-x=0\)

=>\(x=300\)

chờ mình chút sẽ có câu b. k cho mình nha.

5/2+13/6+25/12+41/20+61/30+85/42

=2+1/2+2+1/6+2+1/12+2+1/20+2+1/30+2+1/42
=12+(1/2+1/6+1/12+1/20+1/30+1/42)

=12+(1/1.2+1/2.3+1/3.4+1/4.5+1/5.6+1/6.7)

=12+(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7)

=12+1-1/7

=90/7

5/2+13/6+25/12+41/20+61/30+85/42

=2+1/2+2+1/6+2+1/12+2+1/20+2+1/30+2+1/42
=12+(1/2+1/6+1/12+1/20+1/30+1/42)

=12+(1/1.2+1/2.3+1/3.4+1/4.5+1/5.6+1/6.7)

=12+(1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/7)

=12+1-1/7

=90/7

bạn ko có máy tính ak lâys ra mà bấm chỉ cần làm bàtìm x thôii 

nhưng đây là tính nhanh mà bn

cái này lớp 6 mà bạn

( x - 25) x 17 = 34

=> x - 25 = 34 : 17

     x - 25 = 2

=> x = 2 + 25

     x = 27

145 + (150 - x) = 250

=> 150 - x = 250 - 145

     150 - x = 105

=> x = 150 - 105

     x = 45

(2x - 7) x 81 = 0

=> 2x - 7 = 0 : 81

    2x - 7 = 0

  => 2x = 7

   => x = 7 : 2 = 3,5

x - 90 : 15  = 32

=> x - 6 = 32

=> x = 32 + 6

    x = 38

520 - (x - 5) = 250 : 5

 => 520 - (x - 5) = 50

=> x - 5 = 520 - 50

   x - 5 = 470

=> x = 470 + 5

    x = 475

t i c k nhé!! 346457567684786896789

a ) \(\left(x-5\right).17=34\)

=> \(x-5=2\)

=> \(x=7\)

b ) \(145+\left(150-x\right)=250\)

=> \(150-x=105\)

=> \(x=150-105\)

=> \(x=45\)

c ) \(\left(2.x-7\right).81=0\)

=> \(2x-7=0\)

=> \(2x=7\)

=> \(x=\frac{7}{2}\)

d ) \(x-90:15=32\)

=> \(x-6=32\)

=> \(x=38\)

Mấy cái dấu chấm đó là nhân đó nhé